Improve Your Java/J2ee Skills - Java2Hari

Java Programs

2014-08-07T18:16:00.000+05:30

1. Write a Java program that prints all real solutions to the quadratic equation ax2+bx+c=0.Read in a,b,c and use the quadratic formula.If the discriminant b2-4ac is negative,display a message stating that there are no real roots .

import java.util.Scanner;

class Solutions

{

public static void main(String args[])

{

int a,b,c;

double x,y;

Scanner s=new Scanner(System.in);

System.out.println("Enter the values of a,b, and c");

a=s.nextInt();

b=s.nextInt();

c=s.nextInt();

double f=(b*b)-4*a*c;

System.out.println("F value="+f);

if(f<0)

{

System.out.println("No real roots");

}

else

{

double l=Math.sqrt(f);

System.out.println("Math.sqrt(f)="+l);

x=((-b-l)/(2*a));

y=((-b+l)/(2*a));

System.out.println("Roots of given equation:"+x+"\t"+y);

}

}

}

Output:

Enter the values of a,b,c

2

5

2

Roots of given equation:-0.5 -2.0

2. Write a Java program that uses both recursive and non-recursive functions to print nth value in the Fibonacci sequence .

/*Without recursion*/

import java.util.Scanner;

class Fibonacci

{

public static void main(String[] input)

{

int x,y;

x=Integer.parseInt(input[0]);

y=Integer.parseInt(input[1]);

Scanner s=new Scanner(System.in);

System.out.println(“Enter the value of n:”);

int n=s.nextInt();

int z[]=new int[n];

z[0]=x;

z[1]=y;

for(int i=2;i<n;i++)

{

z[i]=z[i-1]+z[i-2];

}

System.out.println("<------------Fibonacii series------------>");

for(int i=0;i<n;i++)

{

System.out.println(z[i]);

}

}

}

Output:

>java Fibonacci 0 1

Enter the value of n:

8

<------------Fibonacii series------------>

0

1

1

2

3

5

8

13

/*With recursion*/

import java.util.Scanner;

class Fibwithrec

{

public static void main(String[] args)

{

Scanner s=new Scanner(System.in);

System.out.println("Enter the value of n:");

int n=s.nextInt();

System.out.println("Fibonacci series using recursion");

Fiboni f1=new Fiboni();

for(int i=0;i<n;i++)

System.out.println(f1.fibon(i));

}

}

class Fiboni

{

public int fibon(int n)

{

if(n==0 || n==1)

return 1;

else

return fibon(n-1)+fibon(n-2);

}

}

Output:

Enter the value of n:

10

Fibonacci series using recursion

1

1

2

3

5

8

13

21

34

55

3. Write a java program to calculate Factorial of a given number using “Recursion” concept .

import java.io.*;

import java.util.*;

class Factorial

{

int fact(int n)

{

int r;

if(n==1)

return 1;

else

r=fact(n-1)*n;

return r;

}

}

class Recursion

{

public static void main(String args[])throws IOException

{

Factorial f=new Factorial();

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

System.out.println("Enter num to find factorial");

int x=Integer.parseInt(br.readLine());

int k=f.fact(x);

System.out.println("The fatorial of"+x+"is="+k);

}

}

Output:

Enter num to find factorial

5

The fatorial of5is=120

4. Write a java program to check whether given number is prime or not.

import java.util.*;

import java.lang.*;

class PrimeNum

{

public static void main(String args[ ])throws IOException

{

Scanner s=new Scanner(System.in);

System.out.println("Enter the value of n:");

int n=s.nextInt();

int count=0;

for(int i=1;i<=n;i++)

{

if((n%i)==0)

{

count++;

}

}

if(count==2)

{

System.out.println("the num is prime"+n);

}

else

{

System.out.println("the num is not a prime"+n);

}

}

}

Output:

Enter n value

11

the num is prime11

Enter n value

22

the num is not prime22

5. Write a Java program that prompts the user for an integer and then prints out all prime numbers upto that integer .

import java.util.Scanner;

class Prime

{

public static void main(String[] args)

{

int n,p;

Scanner s=new Scanner(System.in);

System.out.println("Enter upto which number prime numbers are needed");

n=s.nextInt();

System.out.println("<------------Prime numbers------------->");

for(int i=2;i<n;i++)

{

p=0;

for(int j=2;j<i;j++)

{

if(i%j==0)

p=1;

}

if(p==0)

System.out.println(i);

}

}

}

Output:

Enter upto which number prime numbers are needed

20

<------------Prime numbers------------->

2

3

5

7

11

13

17

19

6. Write a Java program to print prime numbers in a given range.

import java.util.*;

class PrimeRange

{

public static void main(String args[])

{

int i,j;

Scanner br =new Scanner(System.in);

System.out.println("Enter the starting range");

int s=br.nextInt();

System.out.println("Enter the end range");

int e=br.nextInt();

for(i=s;i<=e;i++)

{

int count=0;

for(j=1;j<=e;j++)

{

if((i%j)==0)

count++;

}

if(count==2)

{

System.out.println(i);

}

}

}

}

Output:

Enter the starting range

10

Enter the end range

30

…Prime series…

11

13

17

19

23

29

7. Write a java program to check whether given number is perfect or not.

import java.util.*;

public class PerfectNumber

{

public static void main(String[] args)

{

System.out.println("Enter any number");

Scanner input = new Scanner(System.in);

int num = input.nextInt();

int perfectNo = 0;

int i;

System.out.println("Factors are:");

for (i = 1; i < num; i++)

{

if (num % i == 0) {

perfectNo += i;

System.out.println(i);

}

}

if (perfectNo == num)

{

System.out.println("number is a perfect number");

} else {

System.out.println("number is not a perfect number");

}

}

Output:

Enter any number

28

Factors are:

1

2

7

14

number is a perfect number

8. Write a Java program to find the total and average of a student marks.

import java.io.*;

class DemoArray

{

public static void main (String args[]) throws IOException

{

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

System.out.println("Enter how many sub");

int n=Integer.parseInt(br.readLine());

int marks[]=new int[n];

for(int i=0;i<n;i++)

{

System.out.println("Enter subject"+(i+1)+"marks");

marks[i]=Integer.parseInt(br.readLine());

}

int tot=0;

System.out.println("The marks are");

for(int i=0;i<n;i++)

{

System.out.println(marks[i]);

tot=tot+marks[i];

}

System.out.println("Total marks="+tot);

float avg=(float)tot/n;

System.out.print("Avarage marks ="+avg);

}

}

Output:

Enter how many subjects

3

Enter subject1 marks

67

Enter subject2 marks

53

Enter subject3 marks

70

The Marks are

67

53

70

total marks=190

Avarage marks=63.333332

9. Write a Java program to display multiplication table.

import java.io.*;

class Multiplication

{

public static void main(String args[])throws IOException

{

Scanner s=new Scanner(System.in);

System.out.println("Enter n value");

int n=s.nextInt();

System.out.println("...Multiplication Table...");

for(int i=1;i<=10;i++)

System.out.println(n+"*"+i+"="+(n*i));

}

}

Output :

Enter n value

5

Multiplication table:

5*1=5

5*2=10

5*3=15

5*4=20

5*5=25

5*6=30

5*7=35

5*8=40

5*9=45

5*10=50

10. Write a Java program that checks whether the given string is palindrome or not.

class Palindrome

{

public static void main(String[] args)

{

StringBuffer s1=new StringBuffer(args[0]);

StringBuffer s2=new StringBuffer(s1);

s1.reverse();

System.out.println(“Given String is:”+s2);

System.out.println(“Reverse String is”+s1);

if(String.valueOf(s1).compareTo(String.valueOf(s2))==0)

System.out.println(“Palindrome”);

else

System.out.println(“Not Palindrome”);

}

}

Output:

Java palindrome madam

Given String is:madam

Reverse String is madam

Palindrome

Java palindrome 121

Given String is:121

Reverse String is 121

Palindrome

11. Write a Java program to sort a given list of names in ascending order.

class Sorting

{

public static void main(String[] input)

{

int k=input.length;

String temp=new String();

String names[]=new String[k+1];

for(int i=0;i<k;i++)

{

names[i]=input[i];

}

for(int i=0;i<k;i++)

for(int j=i+1;j<k;j++)

{

if(names[i].compareTo(names[j])<0)

{

temp=names[i];

names[i]=names[j];

names[j]=temp;

}

}

System.out.println(“Sorted order is”);

for(int i=0;i<k;i++)

{

System.out.println(names[i]);

}

}

}

Output:

Java sorting Harish Ramesh Mahesh Rakesh

Sorted order is

Ramesh

Rakesh

Mahesh

Harish

12. Write a Java Program to multiply two matrices.

import java.util.Scanner;

class Matmul

{

public static void main(String args[])

{

Scanner input=new Scanner(System.in);

System.out.println("Enter size of first matrix:");

int m=input.nextInt();

int n=input.nextInt();

System.out.println("Enter size of second matrix:");

int p=input.nextInt();

int q=input.nextInt();

int a[][]=new int[m][n];

int b[][]=new int[p][q];

int c[][]=new int[m][q];

System.out.println("Enter the first matrix:");

for(int i=0;i<m;i++)

for(int j=0;j<n;j++)

a[i][j]=input.nextInt();

System.out.println("Enter the second matrix:");

for(int i=0;i<p;i++)

for(int j=0;j<q;j++)

b[i][j]=input.nextInt();

System.out.println("Matrix multiplication is as follows:\n");

for(int i=0;i<m;i++)

{

for(int j=0;j<q;j++)

{

c[i][j]=0;

for(int k=0;k<n;k++)

{

c[i][j]+=a[i][k]*b[k][j];

}

}

}

System.out.println("First matrix:\n");

for(int i=0;i<m;i++)

{

for(int j=0;j<n;j++)

{

System.out.print(a[i][j]+"\t");

}

System.out.println("\n");

}

System.out.println("Second matrix:");

for(int i=0;i<p;i++)

{

for(int j=0;j<q;j++)

{

System.out.print(b[i][j]+"\t");

}

System.out.println("\n");

}

System.out.println("Multiplcation:");

for(int i=0;i<m;i++)

{

for(int j=0;j<q;j++)

{

System.out.print(c[i][j]+"\t");

}

System.out.println("\n");

}

}

}

Output:

Enter size of first matrix:

2

2

Enter size of second matrix:

2

2

Enter the first matrix:

1 2

3 4

Enter the second matrix:

1 2

3 4

Matrix multiplication is as follows:

First matrix:

1 2

3 4

Second matrix:

1 2

3 4

Multiplcation:

7 10

15 22

13. Write a java program for array copying method.

import java.io.*;

public class CopyArray

{

public static void main(String[] args)throws IOException

{

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

System.out.println("Enter array length ");

int n=Integer.parseInt(br.readLine());

String array1[]=new String[n];

String array2[]=new String[n];

System.out.println("Enter strings into array1: ");

System.out.println("...................................");

for(int i=0;i<n;i++)

{

System.out.println("Enter the string"+(i+1));

array1[i]=br.readLine();

}

System.out.println("Enter strings into array2: ");

System.out.println("...................................");

for(int i=0;i<n;i++)

{

System.out.println("Enter the string"+(i+1));

array2[i]=br.readLine();

}

System.out.println("Array1:");

System.out.print("[");

for (int i=0; i<n;i++)

{

System.out.print(" "+array1[i]);

}

System.out.print("]");

System.out.println("\nArray2:");

System.out.print("[");

for(int i=0; i<n; i++)

{

System.out.print(" "+ array2[i]);

}

System.out.print("]");

System.out.println("\nAfterCopying:");

System.out.print("[");

System.arraycopy(array1,0,array2,0,2);

for(int i=0;i<n;i++)

{

System.out.print(" "+array2[i]);

}

System.out.print("]");

}

}

Output:

Enter array length

5

Enter strings into array1:

...................................

Enter the string1

q

Enter the string2

w

Enter the string3

e

Enter the string4

r

Enter the string5

t

Enter strings into array2:

...................................

Enter the string1

a

Enter the string2

s

Enter the string3

d

Enter the string4

f

Enter the string5

g

Array1:

[ q w e r t]

Array2:

[ a s d f g]

AfterCopying:

[ q w d f g]

14. Write a program on “Static” method.

import java.io.*;

class StaticMethod

{

static int sum(int a,int b)

{

int c=a+b;

return c;

}

}

class Demo

{

public static void main(String args[])

{

int x=StaticMethod.sum(10,50);

System.out.println(x);

}

}

Output:

sum=60

15. Write a java application on “Static” variable.

import java.io.*;

class Test

{

static int x;

int y;

void inc()

{

x=x+1;

y=y+1;

}

void show()

{

System.out.println("x value is:"+x);

System.out.println("y value is:"+y);

}

}

class Static

{

public static void main(String args[])throws IOException

{

Test t1=new Test();

Test t2=new Test();

System.out.println("First obj values:");

t1.inc();

t1.show();

System.out.println("Second obj values:");

t2.inc();

t2.show();

}

}

Output:

First obj values:

x value is:1

y value is:1

Second obj values:

x value is:2

y value is:1

16. Write a program on “Constructor”.

class Rectangle

{

int l,w;

void getData(int x,int y)

{

l=x;

w=y;

}

int rectArea()

{

return(l*w);

}

}

class RectArea

{

public static void main(String args[ ])

{

Rectangle r1=new Rectangle( );

r1.getData(10,15);

int k=r1.rectArea( );

System.out.print("Area is:"+k);

}

}

Output :

Area is:150

17. Write a java program for “ This ” keyword .

import java.io.*;

class Test

{

int a,b;

void getData()

{

this.a=10;

this.b=20;

}

void show()

{

System.out.println("a value is:"+a);

System.out.println("b value is:"+b);

}

}

class This

{

public static void main(String args[])throws IOException

{

Test t=new Test();

t.getData();

t.show();

}

}

Output:

a value is:10

b value is:20

18. Write a java program on Command Line Arguments.

public class GetCommandLine

{

public static void main(String args[])

{

System.out.println("----->>Getting command line arguments --");

for(int i=0;i<args.length;i++)

{

System.out.println("Argument ["+(i+1)+"] is = "+args[i]);

}

}

}

Output:

>javac GetCommandLine.java

>java GetCommandLine 10 20 30 40 50

----->>Getting command line arguments --

Argument [1] is = 10

Argument [2] is = 20

Argument [3] is = 30

Argument [4] is = 40

Argument [5] is = 50

19. Write a program to find sum of given Command Line Arguments.

import java.io.*;

import java.lang.*;

public class Cmd

{

public static void main(String args[])throws IOException

{

int sum=0;

for(int i=0;i<args.length;i++)

{

int x=Integer.parseInt(args[i]);

sum+=x;

}

System.out.println("sum is="+sum);

}

}

Output:

>javac Cmd.java

>java Cmd 10 15 20 25 30

sum is=100

20. Write a program on Method Overloding.

import java.io.*;

class MethodOverLoad

{

void calValue()

{

int x=20;

x=x*x;

System.out.println("Sqrt of x is:"+x);

}

void calValue(int y)

{

y=y*y*y;

System.out.println("Cube of y is:"+y);

}

void calValue(int m,int n)

{

int z=m*n;

System.out.println("Product of m and n is:"+z);

}

}

class MOV

{

public static void main(String args[])throws IOException

{

MethodOverLoad m=new MethodOverLoad();

m.calValue();

m.calValue(10,20);

m.calValue(10);

}

}

Output:

Sqrt of x is:400

Product of m and n is:200

Cube of y is:1000

21. Write a program on Method Overriding.

import java.io.*;

class One

{

int calculate(int n)

{

return n;

}

}

class Two extends One

{

int calculate(int n)

{

return(n*n);

}

}

class MOR

{

public static void main(String args[])throws IOException

{

Two t=new Two();

int m=t.calculate(3);

System.out.println("Multiplication is:"+m);

}

}

Output:

Multiplication is:9

22. Write a program on Constructor Overloding.

class Test

{

int a,b;

Test()

{

a=1;

b=2;

}

Test(int x)

{

a=b=x;

}

Test(int a, int b)

{

this.a=a;

this.b=b;

}

void show()

{

System.out.println("a value is:"+a);

System.out.println("b value is:"+b);

}

}

class COL

{

public static void main(String args[])

{

Test t1=new Test();

t1.show();

Test t2=new Test(10);

t2.show();

Test t3=new Test(15,25);

t3.show();

}

}

Output:

a value is:1

b value is:2

a value is:10

b value is:10

a value is:15

b value is:25

23. Write a program on InnerClass concept.

class Outer

{

Inner in=new Inner();

class Inner

{

public void sayHello()

{

System.out.println("Hello");

}

}

}

class DemoInner

{

public static void main(String args[])

{

Outer o=new Outer();

o.in.sayHello();

}

}

Output:

Hello

24. Write a Java programme that reads a line of integers and displays each integer and sum of all integers using StringTokenizer class.

import java.util.StringTokenizer;

import java.util.Scanner;

class Tokens

{

public static void main(String[] args)

{

Scanner input=new Scanner(System.in);

System.out.println("Enter no. of tokens u want to add ");

String sentence=input.nextLine();

String temp;

int k,total=0;

StringTokenizer s1=new StringTokenizer(sentence);

System.out.println("Total Number of tokens:"+s1.countTokens());

System.out.println("Tokens are:");

while(s1.hasMoreTokens())

{

temp=s1.nextToken();

k=Integer.parseInt(temp);

total+=k;

System.out.print(k+"\t");

}

System.out.println("\nSum of tokens :"+total);

}

}

Output:

Enter no. of tokens u want to add

5 4 6 1 8 2

Total Number of tokens:6

Tokens are:

5 4 6 1 8 2

Sum of tokens :26

25. Write a java program on “StringTokenizer” class.

import java.util.*;

import java.lang.*;

import java.io.*;

class StringToken

{

public static void main(String args[])throws IOException

{

String str=new String("welcome to java lab");

StringTokenizer stz=new StringTokenizer(str);

System.out.println("No.of words are:");

System.out.println(stz.countTokens());

System.out.println("Tokens are:");

while(stz.hasMoreTokens())

{

System.out.println(stz.nextToken());

}

int count=0;

for(int i=0;i<str.length();i++)

if(str.charAt(i)!=' ')

count++;

System.out.println("Total no of characters:"+count);

}

}

Output:

No.of words are:

4

Tokens are:

welcome

to

java

lab

Total no of characters:16

26. Write a java program on “Inheritence” concept.

interface Father

{

int PROP1=500000;

}

interface Mother

{

int PROP2=800000;

}

class Child implements Father,Mother

{

void property()

{

System.out.println("child property="+(PROP1+PROP2));

}

}

class MultiInher

{

public static void main(String args[])

{

Child ch=new Child();

ch.property();

}

Output:

child property=1300000

27. Write an example using “StringTokenizer” class.

import java.io.*;

import java.util.*;

class DiffData

{

public static void main(String args[])throws IOException

{

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

System.out.println("enter name,age,salary");

String s=br.readLine();

StringTokenizer str=new StringTokenizer(s,",");

String s1=str.nextToken();

String s2=str.nextToken();

String s3=str.nextToken();

s1=s1.trim();

s2=s2.trim();

s3=s3.trim();

String name=s1;

int age=Integer.parseInt(s2);

float salary=Float.parseFloat(s3);

System.out.println("name="+name);

System.out.println("Age="+age);

System.out.println("Salary="+salary);

}

}

Output:

enter name,age,salary

puja,24,15000

name=puja

Age=24

Salary=15000.0

28. Write a java program to make frequency count of words in a given text.

import java.util.*;

import java.lang.*;

import java.io.*;

class Freq

{

public static void main(String[ ] args) throws IOException

{

DataInputStream dis=new DataInputStream(System.in);

System.out.println("Enter number of words");

String str=dis.readLine();

String temp;

StringTokenizer st=new StringTokenizer(str);

int n=st.countTokens( );

String a[ ]=new String[n];

int i=0,count=0;

while(st.hasMoreTokens())

{

a[i]=st.nextToken();

i++;

}

for(int x=1;x<n;x++)

{

for(int y=0;y<n-x;y++)

{

if(a[y].compareTo(a[y+1])>0)

{

temp=a[y];

a[y]=a[y+1];

a[y+1]=temp;

}

}

}

System.out.println("the sorted string are:");

for(i=0;i<n;i++)

{

System.out.println(a[i]+" ");

}

System.out.println();

for(i=0;i<n;i++)

{

count=1;

if(i<n-1)

{

while(a[i].compareTo(a[i+1])==0)

{

count++;

i++;

if(i>=n-1)

{

System.out.println(a[i]+" "+count);

System.exit(0);

}

}

}

System.out.println(a[i]+" "+count);

}

}

}

Output:

Enter number of words

anu puja rani anu vani rani

the sorted string are:

anu

anu

puja

rani

rani

vani

anu 2

puja 1

rani 2

vani 1

29. Write a java program to display Employee data.

import java.io.*;

class Employee

{

int id;

String name;

Employee(int i,String n)

{

id=i;

name=n;

}

void displayData()

{

System.out.println(id+"\t"+name);

}

}

class Group

{

public static void main(String args[])throws IOException

{

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

Employee arr[]=new Employee[5];

for(int i=0;i<5;i++)

{

System.out.println("enter id");

int id=Integer.parseInt(br.readLine());

System.out.println("enter name");

String name=br.readLine();

arr[i]=new Employee(id,name);

}

System.out.println("Employee data");

for(int i=0;i<arr.length;i++)

{

arr[i].displayData();

}

}

}

Output:

1

enter name

rani

enter id

2

enter name

bhavya

enter id

3

enter name

madhu

enter id

4

enter name

peethi

enter id

5

enter name

sonu

Employee data

1 rani

2 bhavya

3 madhu

4 peethi

5 sonu

30. Write a java program using “Super” keyword.

import java.io.*;

class A

{

int a;

A(int a)

{

this.a=a;

}

void showA()

{

System.out.println("The value of a is "+a);

}

}

class B extends A

{

int b;

B(int a,int b)

{

super(a);

this.b=b;

}

void showB()

{

System.out.println("The value of b is "+b);

}

}

class SuperKey

{

public static void main(String args[])

{

B o=new B(100,200);

o.showA();

o.showB();

}

}

Output:

The value of a is 100

The value of b is 200

31. Write a java program using “Abstract class”.

abstract class A

{

abstract void call();

void callMethod()

{

System.out.println("This is concreate method");

}

}

class B extends A

{

void call()

{

System.out.println("This is implementation of class ");

}

}

class AbstractDemo

{

public static void main(String args[])

{

B b=new B();

b.call();

b.callMethod();

}

}

Output:

This is implementation of class

This is concreate method

32. Write a java program on creating and implementation of package.

//creating own package.

package pack;

public class Add

{

public int i,j;

public Add(int i,int j)

{

this.i=i;

this.j=j;

}

public void add()

{

System.out.println("Details");

System.out.println(".................");

System.out.println("Additon is: "+(i+j));

}

}

//implementation of a package.

import pack.Add;

class PackExe

{

public static void main(String args[])

{

Add a=new Add(20,45);

a.add();

}

}

Output:

>javac -d . Add.java

>javac PackExe.java

>java PackExe

Details

.................

Additon is: 65

33. Write a java program on “Interface” concept.

interface MyInterface

{

public void sayHello();

}

class Subclass implements MyInterface

{

public void sayHello()

{

System.out.println("hello");

}

}

class DemoInterface

{

public static void main(String args[ ])

{

Subclass i=new Subclass();

i.sayHello();

}

}

Output:

hello

34. Write a Java program that reads on file name from the user then displays information about whether the file exists,whether the file is readable,whether the file is writable,the type of the file and the length of the file in bytes.

import java.util.Scanner;

import java.io.File;

class FileDemo

{

public static void main(String[] args)

{

Scanner input=new Scanner(System.in);

String s=input.nextLine();

File f1=new File(s);

System.out.println("File Name:"+f1.getName());

System.out.println("Path:"+f1.getPath());

System.out.println("Abs Path:"+f1.getAbsolutePath());

System.out.println("Parent:"+f1.getParent());

System.out.println("This file is:"+(f1.exists()?"Exists":"Does not exists"));

System.out.println("Is file:"+f1.isFile());

System.out.println("Is Directory:"+f1.isDirectory());

System.out.println("Is Readable:"+f1.canRead());

System.out.println("IS Writable:"+f1.canWrite());

System.out.println("Is Absolute:"+f1.isAbsolute());

System.out.println("File Last Modified:"+f1.lastModified());

System.out.println("File Size:"+f1.length()+"bytes");

System.out.println("Is Hidden:"+f1.isHidden());

}}

Output:

Fibonacci.java

File Name:Fibonacci.java

Path: Fibonacci.java

Abs Path: c:\sameer\Fibonacci.java

Parent: Null

This file is:Exists

Is file:true

Is Directory:false

Is Readable:true

Is Writable:true

Is Absolute:false

File Last Modified:1206324301937

File Size: 406 bytes

Is Hidden:false

35. Wtire a Java program that reads a file and displays a file and displays the file on the screen,with a line number before each line.

import java.io.*;

class Linenum

{

public static void main(String[] args)throws IOException

{

FileInputStream fil;

LineNumberInputStream line;

int i;

try

{

fil=new FileInputStream(args[0]);

line=new LineNumberInputStream(fil);

}

catch(FileNotFoundException e)

{

System.out.println("No such file found");

return;

}

do

{

i=line.read();

if(i=='\n')

{

System.out.println();

System.out.print(line.getLineNumber()+" ");

}

else

System.out.print((char)i);

}while(i!=-1);

fil.close();

line.close();

}

}

Output:

Demo.java

class Demo

1 {

2 public static void main(java Demo beta gamma delta)

3 {

4 int n = 1 ;

5 System.out.println("The word is " + args[ n ] );

6 }

7 }

8?

36. Write a Java program that displays the number of characters,lines and words in a given text file.

import java.io.*;

class Wordcount

{

public static int words=0;

public static int lines=0;

public static int chars=0;

public static void wc(InputStreamReader isr)throws IOException

{

int c=0;

boolean lastwhite=true;

while((c=isr.read())!=-1)

{

++chars;

if(c=='\n')

lines++;

if(c=='\t' || c==' ' || c=='\n')

++words;

if(chars!=0)

++chars;

}

}

public static void main(String[] args)

{

FileReader fr;

try

{

if(args.length==0)

{

wc(new InputStreamReader(System.in));

}

else

{

for(int i=0;i<args.length;i++)

{

fr=new FileReader(args[i]);

wc(fr);

}

}

}

catch(IOException ie)

{

return;

}

System.out.println("No. of Lines"+lines+"\nNo. of Words"+words+"\nNo. of chars"+chars);

}

}

Output:

This is cse

^Z

No. of Lines1

No. of Words3

No. of chars13

37. Write a java program on “try,catch,finally” blocks.

class DemoEx

{

public static void main(String args[])

{

try

{

int a,b,c;

a=Integer.parseInt(args[0]);

b=Integer.parseInt(args[1]);

c=a/b;

System.out.println("Result is ="+c);

}

catch (ArithmeticException ae)

{

System.out.println("not enter zeros");

}

catch (ArrayIndexOutOfBoundsException e)

{

System.out.println("enter at least 2 no's");

}

catch (NumberFormatException ne)

{

System.out.println("enter int values");

}

finally

{

System.out.println("This is final");

}

}

}

Output:

>java DemoEx 4 0

not enter zeros

This is final

>java DemoEx 4

enter at least 2 no's

This is final

>java DemoEx 4.2 3.4

enter int values

This is final

>java DemoEx 4 2

Result is =2

This is final

38. Write a java program on creating own exception.

class VException extends Exception

{

VException(String s)

{

super(s);

}

}

class Voting

{

static void displayvote(int age)throws VException

{

if(age<19)

throw new VException("Invalid age");

System.out.println("Candidate is eligible to vote");

}

}

class UserExe

{

public static void main(String args[])

{

int age = Integer.parseInt(args[0]);

try

{

Voting.displayvote(age);

}

catch(VException e)

{

System.out.println(e.getMessage());

}

}

}

Output:

>java UserExe 23

Candidate is eligible to vote

>java UserExe 16

Invalid age

39. Write a java program using “HashSet” method..

import java.util.*;

class HS

{

public static void main(String args[])

{

HashSet<String> hs=new HashSet<String>();

hs.add("india");

hs.add("us");

hs.add("uk");

hs.add("japan");

System.out.println("HashSet ="+hs);

Iterator it=hs.iterator();

System.out.println("elements using iterator");

while(it.hasNext())

{

String s=(String)it.next();

System.out.println(s);

}

}

}

Output:

HashSet =[

uk, japan, us, india]

elements using iterator

uk

japan

us

india

40 . Write a Java program that implements stack ADT.

import java.lang.*;

import java.io.*;

import java.util.*;

interface Mystack

{

int n=10;

public void pop();

public void push();

public void display();

}

class Stackimp implements Mystack

{

int stack[]=new int[n];

int top=-1;

public void push()

{

try

{

DataInputStream dis=new DataInputStream(System.in);

if(top==(n-1))

{

System.out.println("overflow");

return;

}

else

{

System.out.println("enter element");

int ele=Integer.parseInt(dis.readLine());

stack[++top]=ele;

}

}

catch(Exception e)

{

System.out.println("e");

}

}

public void pop()

{

if(top<0)

{

System.out.println("underflow");

return;

}

else

{

int popper=stack[top];

top--;

System.out.println("popped element" +popper);

}

}

public void display()

{

if(top<0)

{

System.out.println("empty");

return;

}

else

{

String str=" ";

for(int i=0;i<=top;i++)

str=str+" "+stack[i];

System.out.println("elements are"+str);

}

}

}

class StackAdt

{

public static void main(String arg[])throws IOException

{

DataInputStream dis=new DataInputStream(System.in);

Stackimp stk=new Stackimp();

int ch=0;

do{

System.out.println("\nMenu is as follows:\n1.push\t2.pop\t3.display\t4.exit");

System.out.println("\nEnter ur choice");

ch=Integer.parseInt(dis.readLine());

switch(ch)

{

case 1:stk.push();

break;

case 2:stk.pop();

break;

case 3:stk.display();

break;

case 4:System.exit(0);

}

}while(ch<=5);

}

}

Output:

Menu is as follows:

1.Push

2.Pop

3.Display

4.Exit

Enter ur choice:1

Enter element to push :12

Menu is as follows:

1.Push

2.Pop

3.Display

4.Exit

Enter ur choice:1

Enter element to push:13

Menu is as follows:

1.Push

2.Pop

3.Display

4.Exit

Enter ur choice:3

12

13

Menu is as follows:

1.Push

2.Pop

3.Display

4.Exit

Enter ur choice:2

Popped item:13

Menu is as follows:

1.Push

2.Pop

3.Display

4.Exit

Enter ur choice:2

Popped item:12

Menu is as follows:

1.Push

2.Pop

3.Display

4.Exit

Enter ur choice:3

Stack is empty

41. Write a Java program that converts infix expression into postfix form.

import java.io.*;

class stack

{

char stack1[]=new char[20];

int top;

void push(char ch)

{

top++;

stack1[top]=ch;

}

char pop()

{

char ch;

ch=stack1[top];

top--;

return ch;

}

int pre(char ch)

{

switch(ch)

{

case '-':return 1;

case '+':return 1;

case '*':return 2;

case '/':return 2;

}

return 0;

}

boolean operator(char ch)

{

if(ch=='/'||ch=='*'||ch=='+'||ch=='-')

return true;

else

return false;

}

boolean isAlpha(char ch)

{

if(ch>='a'&&ch<='z'||ch>='0'&&ch=='9')

return true;

else

return false;

}

void postfix(String str)

{

char output[]=new char[str.length()];

char ch;

int p=0,i;

for(i=0;i<str.length();i++)

{

ch=str.charAt(i);

if(ch=='(')

{

push(ch);

}

else if(isAlpha(ch))

{

output[p++]=ch;

}

else if(operator(ch))

{

if(stack1[top]==0||(pre(ch)>pre(stack1[top]))||stack1[top]=='(')

{

push(ch);

}

}

else if(pre(ch)<=pre(stack1[top]))

{

output[p++]=pop();

push(ch);

}

else if(ch=='(')

{

while((ch=pop())!='(')

{

output[p++]=ch;

}

}

}

while(top!=0)

{

output[p++]=pop();

}

for(int j=0;j<str.length();j++)

{

System.out.print(output[j]);

}

}

}

class intopost

{

public static void main(String[] args)throws Exception

{

String s;

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

stack b=new stack();

System.out.println("Enter input string");

s=br.readLine();

System.out.println("Input String:"+s);

System.out.print("Output String:");

b.postfix(s);

}

}

Output:

Enter input string

a+b*c

Input String:a+b*c

Output String:abc*+

Enter input string

a+(b*c)/d

Input String:a+(b*c)/d

Output String:abc*d/)(+

42. Write an applet that displays a simple message.

import java.io.*;

import java.awt.*;

import java.applet.Applet;

/*<applet code="AppletTest.class" height=100 width=500></applet>*/

public class AppletTest extends Applet

{

public void paint(Graphics g)

{

g.drawString("This is CSE IInd Year IInd sem",50,60);

setBackground(Color.yellow);

setForeground(Color.red);

}

}

Output:

>javac AppletTest.java

>appletviewer AppletTest.java

43. Develop an applet that receives an integer in one text field, and computes as factorial value and returns it in another text field,when the button named “Compute” is clicked.

import java.awt.*;

import java.awt.event.*;

import java.applet.Applet;

/*<applet code="AddEvent.class" height=100 width=500></applet>*/

public class AddEvent extends Applet implements ActionListener

{

TextField tf1;

TextField tf2;

Button b;

Label l;

public void init()

{

setBackground(Color.cyan);

setForeground(Color.blue);

l=new Label("Enter the number & press the button");

tf1=new TextField("",5);

tf2=new TextField("",10);

b=new Button("press me");

add(l);

add(tf1);

add(tf2);

add(b);

b.addActionListener(this);

}

public void actionPerformed(ActionEvent ae)

{

String str=ae.getActionCommand();

String str1;

int fact=1;

if(str=="press me")

{

int n=Integer.parseInt(tf1.getText());

for(int i=1;i<=n;i++)

fact=fact*i;

str1=""+fact;

tf2.setText(str1);

}

}

}

Output:

>javac AddEvent.java

>appletviewer AddEvent.java

44. Write a Java program that works as a simple calculator.Use a grid layout to arrange buttons for the digits and for the + - * % operations.Add a text field to display the result.

import java.awt.*;

import java.applet.*;

import java.awt.event.*;

/*<applet code="Calculator.class" width=200 height=200></applet>*/

public class Calculator extends Applet implements ActionListener

{

TextField t1;

String a="",b;

String oper="",s="",p="";

int first=0,second=0,result=0;

Panel p1;

Button b0,b1,b2,b3,b4,b5,b6,b7,b8,b9;

Button add,sub,mul,div,mod,res,space;

public void init()

{

setBackground(Color.cyan);

setForeground(Color.blue);

Panel p2,p3;

p1=new Panel();

p2=new Panel();

p3=new Panel();

t1=new TextField(a,20);

p1.setLayout(new BorderLayout());

p2.add(t1);

b0=new Button("0");

b1=new Button("1");

b2=new Button("2");

b3=new Button("3");

b4=new Button("4");

b5=new Button("5");

b6=new Button("6");

b7=new Button("7");

b8=new Button("8");

b9=new Button("9");

add=new Button("+");

sub=new Button("-");

mul=new Button("*");

div=new Button("/");

mod=new Button("%");

res=new Button("=");

space=new Button("c");

p3.setLayout(new GridLayout(4,4));

b0.addActionListener(this);

b1.addActionListener(this);

b2.addActionListener(this);

b3.addActionListener(this);

b4.addActionListener(this);

b5.addActionListener(this);

b6.addActionListener(this);

b7.addActionListener(this);

b8.addActionListener(this);

b9.addActionListener(this);

add.addActionListener(this);

sub.addActionListener(this);

mul.addActionListener(this);

div.addActionListener(this);

mod.addActionListener(this);

res.addActionListener(this);

space.addActionListener(this);

p3.add(b0);

p3.add(b1);

p3.add(b2);

p3.add(b3);

p3.add(b4);

p3.add(b5);

p3.add(b6);

p3.add(b7);

p3.add(b8);

p3.add(b9);

p3.add(add);

p3.add(sub);

p3.add(mul);

p3.add(div);

p3.add(mod);

p3.add(res);

p3.add(space);

p1.add(p2,BorderLayout.NORTH);

p1.add(p3,BorderLayout.CENTER);

add(p1);

}

public void actionPerformed(ActionEvent ae)

{

a=ae.getActionCommand();

if(a=="0"||a=="1"||a=="2"||a=="3"||a=="4"||a=="5"||a=="6"||a=="7"||a=="8"||

a=="9")

{

t1.setText(t1.getText()+a);

}

if(a=="+"||a=="-"||a=="*"||a=="/"||a=="%")

{

first=Integer.parseInt(t1.getText());

oper=a;

t1.setText("");

}

if(a=="=")

{

if(oper=="+")

result=first+Integer.parseInt(t1.getText());

if(oper=="-")

result=first-Integer.parseInt(t1.getText());

if(oper=="*")

result=first*Integer.parseInt(t1.getText());

if(oper=="/")

result=first/Integer.parseInt(t1.getText());

if(oper=="%")

result=first%Integer.parseInt(t1.getText());

t1.setText(result+"");

}

if(a=="c")

t1.setText("");

}

}

Output:

>javac Calculator.java

>appletviewer Calculator.java

45. Write a Java program for handling mouse events.

import java.awt.*;

import java.awt.event.*;

import java.applet.*;

/*

<applet code="Mouse" width=500 height=500>

</applet>

*/

public class Mouse extends Applet

implements MouseListener,MouseMotionListener

{

int X=0,Y=20;

String msg="MouseEvents";

public void init()

{

addMouseListener(this);

addMouseMotionListener(this);

setBackground(Color.black);

setForeground(Color.red);

}

public void mouseEntered(MouseEvent m)

{

setBackground(Color.magenta);

showStatus("Mouse Entered");

repaint();

}

public void mouseExited(MouseEvent m)

{

setBackground(Color.red);

showStatus("Mouse Exited");

repaint();

}

public void mousePressed(MouseEvent m)

{

X=10;

Y=20;

msg="NEC";

setBackground(Color.green);

repaint();

}

public void mouseReleased(MouseEvent m)

{

X=10;

Y=20;

msg="Engineering";

setBackground(Color.blue);

repaint();}

public void mouseMoved(MouseEvent m)

{

X=m.getX();

Y=m.getY();

msg="College";

setBackground(Color.cyan);

showStatus("Mouse Moved");

repaint();

}

public void mouseDragged(MouseEvent m)

{

msg="CSE";

setBackground(Color.yellow);

showStatus("Mouse Moved"+m.getX()+" "+m.getY());

repaint();

}

public void mouseClicked(MouseEvent m)

{

msg="Students";

setBackground(Color.pink);

showStatus("Mouse Clicked");

repaint();

}

public void paint(Graphics g)

{

g.drawString(msg,X,Y);

}}

Output:

>javac Mouse.java

>appletviewer Mouse.java

46. Write a program for handling KeyBoard events.

import java.awt.*;

import java.awt.event.*;

import java.applet.*;

/*

<applet code="Key" width=300 height=400>

</applet>

*/

public class Key extends Applet

implements KeyListener

{

int X=20,Y=30;

String msg="KeyEvents--->";

public void init()

{

addKeyListener(this);

requestFocus();

setBackground(Color.green);

setForeground(Color.blue);

}

public void keyPressed(KeyEvent k)

{

showStatus("KeyDown");

int key=k.getKeyCode();

switch(key)

{

case KeyEvent.VK_UP:

showStatus("Move to Up");

break;

case KeyEvent.VK_DOWN:

showStatus("Move to Down");

break;

case KeyEvent.VK_LEFT:

showStatus("Move to Left");

break;

case KeyEvent.VK_RIGHT:

showStatus("Move to Right");

break;

}

repaint();

}

public void keyReleased(KeyEvent k)

{

showStatus("Key Up");

}

public void keyTyped(KeyEvent k)

{

msg+=k.getKeyChar();

repaint();

}

public void paint(Graphics g)

{

g.drawString(msg,X,Y);

}

}

Output:

47. Write a java program that creates three threads.First thread displays”Good Morning”every one second,the second thread displays “Hello” every two seconds and the third threaddisplays “Welcome” every three seconds.

class Frst implements Runnable

{

Thread t;

Frst()

{

t=new Thread(this);

System.out.println("Good Morning");

t.start();

}

public void run()

{

for(int i=0;i<10;i++)

{

System.out.println("Good Morning"+i);

try

{

t.sleep(1000);

}

catch(Exception e)

{

System.out.println(e);

}

}

}

}

class sec implements Runnable

{

Thread t;

sec()

{

t=new Thread(this);

System.out.println("hello");

t.start();

}

public void run()

{

for(int i=0;i<10;i++)

{

System.out.println("hello"+i);

Try

{

t.sleep(2000);

}

catch(Exception e)

{

System.out.println(e);

}

}

}

}

class third implements Runnable

{

Thread t;

third()

{

t=new Thread(this);

System.out.println("welcome");

t.start();

}

public void run()

{

for(int i=0;i<10;i++)

{

System.out.println("welcome"+i);

try{

t.sleep(3000);

}

catch(Exception e)

{

System.out.println(e);

}

}

}

}

public class Multithread

{

public static void main(String arg[])

{

new Frst();

new sec();

new third();

}

}

Output:

Good Morning

hello

welcome

Good Morning0

hello0

welcome0

Good Morning1

hello1

welcome1

Good Morning2

hello2

welcome2

Good Morning3

hello3

welcome3

Good Morning4

hello4

welcome4

Good Morning5

hello5

welcome5

Good Morning6

hello6

welcome6

Good Morning7

hello7

welcome7

Good Morning8

hello8

welcome8

Good Morning9

hello9

welcome9

48. Write a java program on “ThreadGroup”.

class ThreadGroupPro

{

public static void main(String args[])

{

ThreadGroup tg=new ThreadGroup("subgroup1");

Thread t1=new Thread(tg,"Thread1");

Thread t2=new Thread(tg,"Thread2");

Thread t3=new Thread(tg,"Thread3");

tg=new ThreadGroup("subgroup2");

Thread t4=new Thread(tg,"Thread4");

Thread t5=new Thread(tg,"Thread5");

tg=Thread.currentThread().getThreadGroup();

int age=tg.activeGroupCount();

System.out.println("No.of sub groups="+age);

System.out.println("Groups are");

tg.list();

}

}

Output:

No.of sub groups=2

Groups are

java.lang.ThreadGroup[name=main,maxpri=10]

Thread[main,5,main]

java.lang.ThreadGroup[name=subgroup1,maxpri=10]

java.lang.ThreadGroup[name=subgroup2,maxpri=10]

49. Write a Java program that correctly implements producer consumer problem using the concept of inter thread communication.

class Q

{

int n;

boolean valueSet=false;

synchronized int get()

{

if(!valueSet)

try

{

wait();

}

catch(InterruptedException e)

{

System.out.println("Interrupted Exception caught");

}

System.out.println("Got:"+n);

valueSet=false;

notify();

return n;

}

synchronized void put(int n)

{

if(valueSet)

try

{

wait();

}

catch(InterruptedException e)

{

System.out.println("Interrupted Exception caught");

}

this.n=n;

valueSet=true;

System.out.println("Put:"+n);

notify();

}

}

class Producer implements Runnable

{

Q q;

Producer(Q q)

{

this.q=q;

new Thread(this,"Producer").start();

}

public void run()

{

int i=0;

while(true)

{

q.put(i++);

}

}

}

class Consumer implements Runnable

{

Q q;

Consumer(Q q)

{

this.q=q;

new Thread(this,"Consumer").start();

}

public void run()

{

while(true)

{

q.get();

}

}

}

class ProdCons

{

public static void main(String[] args)

{

Q q=new Q();

new Producer(q);

new Consumer(q);

System.out.println("Press Control-c to stop");

}

}

Output:

Put:0

Press Control-c to stop

Got:0

Put:1

Got:1

Put:2

Got:2

Put:3

Got:3

Put:4

Got:4

Put:5

Got:5

Put:6

Got:6

Put:7

Got:7

Put:8

Got:8

Put:9

Got:9

Put:10

Got:10

Put:11

Got:11

Put:12

Got:12

Put:13

Got:13

Put:14

Got:14

Put:15

Got:15

50. Write a program that creates a user interface to perform integer divisions.The user enters two numbers int the textfields,Num1 and Num2.The divison of Num1 and Num2 is displayed in the Result field when the Divide button is clicked.If Num1 or Num2 were not an integer,the program would throw a NumberFormatException.If Num2 were Zero,the programwould throw an ArithmeticException Display the exception in a message dialog box.

import java.awt.*;
import java.awt.event.*;
import java.applet.Applet;
import javax.swing.*;
/*<applet code="Divide.class" height=100 width=500></applet>*/
public class Divide extends Applet implements ActionListener
{
TextField tf1;
TextField tf2;
Button b;
TextField tf3;
Label l;
public void init()
{
setBackground(Color.cyan);
setForeground(Color.blue);
l=new Label("enter the numbers and press divide button");
tf1=new TextField("",5);
tf2=new TextField("",5);
tf3=new TextField("",5);
b=new Button("Divide");
add(l);
add(tf1);
add(tf2);
add(b);
add(tf3);
b.addActionListener(this);
}
public void actionPerformed(ActionEvent ae)
{
if(ae.getActionCommand()=="Divide")
{
try{
int n1=Integer.parseInt(tf1.getText());
int n2=Integer.parseInt(tf2.getText());
int n=n1/n2;
tf3.setText(""+n);
}
catch(ArithmeticException e1)
{
JOptionPane.showMessageDialog(null,"Arthimetic Exception");
}
catch(NumberFormatException e2)
{
JOptionPane.showMessageDialog(null,"NumberFormatException");
}
}
}
}

Output:
>javac Divide.java

>appletviewer Divide.java

51. Write a java program that stimulates a traffic light. The program lets the user select
one of three lights: red, yellow, or green. When a radio button is selected, the light is
turned on, and only one light can be on at a time No light is on when the program starts.

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
/*<applet code="CBGroup" width=250 height=200></applet>*/
public class CBGroup extends Applet implements ItemListener
{
String msg="";
Checkbox Red,Green,Yellow;
CheckboxGroup cbg;
public void init()
{
setBackground(Color.cyan);
cbg=new CheckboxGroup();
Red=new Checkbox("RED",cbg,false);
Green=new Checkbox("GREEN",cbg,false);
Yellow=new Checkbox("YELLOW",cbg,false);
add(Red);
add(Yellow);
add(Green);
Red.addItemListener(this);
Green.addItemListener(this);
Yellow.addItemListener(this);
}
public void itemStateChanged(ItemEvent ie)
{
repaint();
}
public void paint(Graphics g)
{
//g.drawOval(10,10,50,50);
if(cbg.getSelectedCheckbox().getLabel()=="RED")
{
g.setColor(Color.red);
g.fillOval(10,10,50,50);
}
if(cbg.getSelectedCheckbox().getLabel()=="YELLOW")
{
g.setColor(Color.yellow);
g.fillOval(10,10,50,50);
}
if(cbg.getSelectedCheckbox().getLabel()=="GREEN")
{
g.setColor(Color.green);
g.fillOval(10,10,50,50);
}
}
}

Output:

>javac CBGroup.java

>appletviewer CBGroup.java

52. Write a Java program that allows the user to draw lines, rectangles and ovals

import java.awt.*;

import java.applet.*;

/*<applet code="Draw.class" width=200 height=200>

</applet>*/

public class Draw extends Applet

{

public void paint(Graphics g)

{

for(int i=0;i<=250;i++)

{

Color c1=new Color(35-i,55-i,110-i);

g.setColor(c1);

g.drawRect(250+i,250+i,100+i,100+i);

g.drawOval(100+i,100+i,50+i,50+i);

g.drawLine(50+i,20+i,10+i,10+i);

}

}

}

Output: >appletviewer Draw.java

53. Write a java program to create an abstract class named Shape that contains an empty
method name numberOfSides().Provide three classes named Trapezoid,Traingle and Hexagon
such that each of the classes extends the class Shape. Each one of the classes contains only
the method numberOfSides() that shows the number of sides in the given geometrical
figures.

import java.lang.*;
abstract class Shape
{
abstract void numberOfSides();
}
class Traingle extends Shape
{
public void numberOfSides()
{
System.out.println("three");
}}
class Trapezoid extends Shape
{
public void numberOfSides()
{
System.out.println("four");
}}
class Hexagon extends Shape
{
public void numberOfSides()
{
System.out.println("six");
}}
public class Sides
{
public static void main(String arg[])
{
Traingle T=new Traingle();
Trapezoid Ta=new Trapezoid();
Hexagon H=new Hexagon();
T.numberOfSides();
Ta.numberOfSides();
H.numberOfSides();
}}
Output:
three
four
six

54. Write a java program for FlowLayout.

import java.awt.*;

class DemoFlowLayout extends Frame

{

public DemoFlowLayout()

{

setLayout(new FlowLayout());

for(int i=1;i<=20;i++)

{

Button b=new Button(String.valueOf(i));

add(b);

}

setBackground(Color.cyan);

setForeground(Color.blue);

setSize(100,200);

setVisible(true);

}

public static void main(String args[])

{

DemoFlowLayout df=new DemoFlowLayout();

}

}

Output:

55. Write a java program for GridLayout.

import java.awt.*;

import java.applet.*;

class DemoGridLayout extends Frame

{

public DemoGridLayout()

{

setLayout(new GridLayout(5,4));

for(int i=1;i<=20;i++)

{

Button b=new Button(String.valueOf(i));

add(b);

}

setBackground(Color.cyan);

setForeground(Color.blue);

setSize(100,200);

setVisible(true);

}

public static void main(String args[])

{

DemoGridLayout dg=new DemoGridLayout();

}

}

Output:

56. Write a java program for BorderLayout.

import java.awt.*;

import java.applet.*;

import java.awt.event.*;

class DemoBoarder extends Frame

{

Button b1,b2,b3,b4,b5;

public DemoBoarder()

{

setForeground(Color.blue);

setLayout(new BorderLayout());

b1=new Button("one");

b2=new Button("two");

b3=new Button("three");

b4=new Button("four");

b5=new Button("five");

add(b1,"East");

add(b2,"West");

add(b3,"North");

add(b4,"South");

add(b5,"Center");

setSize(300,300);

setVisible(true);

}

public static void main(String args[])

{

DemoBoarder db=new DemoBoarder();

}

}

Output:

57. Write a java program for CardLayout.

import java.awt.*;

import java.applet.*;

import java.awt.event.*;

/*<APPLET

CODE=CardLayoutDemo.class

WIDTH=400

HEIGHT=200>

</APPLET>

*/

public class CardLayoutDemo extends Applet implements ActionListener

{

CardLayout cl;

Panel p;

public void init()

{

setBackground(Color.cyan);

setForeground(Color.blue);

p=new Panel();

add(p);

cl=new CardLayout();

p.setLayout(cl);

initialisation();

}

void initialisation()

{

Button b1=new Button("Button1");

Button b2=new Button("Button2");

Button b3=new Button("Button3");

b1.addActionListener(this);

b2.addActionListener(this);

b3.addActionListener(this);

p.add(b1,"Button1");

p.add(b2,"Button2");

p.add(b3,"Button3");

}

public void actionPerformed(ActionEvent e)

{

cl.next(p);

}

}

Output:

>javac CardLayoutDemo.java

>appletviewer CardLayoutDemo.java

58. Write a java program on “Server and Client”.

/*Server.java*/

import java.io.*;

import java.net.*;

class Server

{

public static void main(String args[]) throws Exception

{

ServerSocket ss=new ServerSocket(777);

Socket s=ss.accept();

System.out.println("connection establisted");

OutputStream obj=s.getOutputStream();

PrintStream ps=new PrintStream(obj);

String str="Hello client";

ps.println(str);

ps.println("Good Bye");

ps.close();

ss.close();

s.close();

}

}

/*Client.java*/

import java.io.*;

import java.net.*;

class Client

{

public static void main(String args[]) throws Exception

{

Socket s=new Socket("localhost",777);

InputStream obj=s.getInputStream();

BufferedReader br=new BufferedReader(new InputStreamReader(obj));

String str;

while((str=br.readLine())!=null)

System.out.println("from Server1:"+str);

br.close();

s.close();

}

}

Output:

From Server:

>javac Server1.java

>java Server1

connection establisted

From Client:

>javac Client1.java

>java Client1

from Server1:Hello client

from Server1:Good Bye

59. Write a java program on “Canvas”.

import java .awt.*;

import java.applet.*;

/*<APPLET CODE=CanvasDemo.class WIDTH=300 HEIGHT=300>

</APPLET>*/

public class CanvasDemo extends Applet

{

public void init()

{

setBackground(Color.red);

CanvasExe ce=new CanvasExe();

ce.setSize(200,200);

ce.setBackground(Color.blue);

ce.setVisible(true);

add(ce);

}

class CanvasExe extends Canvas

{

public void paint(Graphics g)

{

setForeground(Color.green);

g.fillOval(30,0,80,80);

g.drawString("Hello",50,100);

}}}

Output:

Youtube Video Downloader For Google Chrome

2014-07-03T18:45:00.004+05:30

Youtube Video Downloader For Google Chrome

>>Here first we need to install the script plugin.

Open Google Chrome Browser and click on setting.
Click on "Extensions" (Left side top corner)
Click on "Get more extensions" (Left side bottom of the page).
Search for "tampermonkey" and select it.
Here you can find the tampermonkey picture and Click on "+ FREE" buttor (Green color button)
Click on "Add"
Script plugin successfully installed. So now we can import any type of script in your google chrome through tampermonkey extensions.

>>Here second we need to import the script to download the youtube videos.

Click Here to install/import the script.
Click on "Install"
Please close and re-open you google chrome.
Enjoy!!!

[More details]

How to Install MySQL on a Windows Server

2013-01-24T08:50:00.000+05:30

Install MySQL on a Windows Server

The following article explains how to install MySQL on a Windows Server. The process involves downloading the latest version of MySQL directly to your Windows server and then installing the software. MySQL is a free product. Once installed, you may begin creating and using MySQL databases on your server.

To install MySQL, please follow these steps:

Log into your server through Terminal Services or Remote Desktop Connection.
Open a Web browser and load http://dev.mysql.com/downloads/
Download Windows (x86) ZIP/Setup.exe (there's no need to sign up. It is a free download).
Unzip the file you downloaded above and run Setup.exe.
Click Next to begin the installation wizard.
Accept the License Agreement and click Next.
Select Typical Installation and click Next.
Click Install. The installation will take a few moments.
Click Next until you reach the Wizard Completed screen.
Check Configure the MySQL Server now and click Finish.
Click Next to begin the MySQL Server Instance Configuration Wizard.
Select Detailed Configuration and click Next.
Select Server Machine and click Next.
Select Multifunctional Database and click Next.
For InnoDB Tablespace Settings, leave the default settings and click Next.
Select Online Transaction Processing (OLTP) and click Next.
Check Enable TCP/IP Networking, leave the default Port Number and click Next.
Select Standard Character Set and click Next.
Check Install as Windows Service, uncheck Include BIN directory in Windows PATH and click Next.
Enter a password for your root user, uncheck Create an Anonymous Account and click Next.
Click Execute to complete the installation.

JQuery Auto Complete Box

2012-03-13T23:25:00.002+05:30

JQuery Auto Complete Box

$('#query').autocomplete(options) now returns an Autocomplete instance only for the first matched element.

Autocomplete functionality can be disabled or enabled programmatically.
var ac = $('#query').autocomplete(options);
ac.disable();
ac.enable();

Options can be changed programmatically at any time, only options that are passed get set:
ac.setOptions({ zIndex: 1001 });

If you need to pass additional parameters, you can set them via setOptions too:
ac.setOptions({ params: { first:'John', last:'Doe' } });

New parameters when initializing autocomplete. They can also be set via setOptions.

- zIndex: default value is 9999.

- fnFormatResult: function that formats values that are displayed in the autosuggest list. It takes three parameters: suggested value, data and current query value. Default function for this:
var reEscape = new RegExp('(\\' + ['/', '.', '*', '+', '?', '|', '(', ')', '[', ']', '{', '}', '\\'].join('|\\') + ')', 'g');

function fnFormatResult(value, data, currentValue) {
var pattern = '(' + currentValue.replace(reEscape, '\\$1') + ')';
return value.replace(new RegExp(pattern, 'gi'), '<strong>$1<\/strong>');
}

Installation:

Include jQuery in your header. After its included, add autocomplete script.
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="jquery.autocomplete.js"></script>

How to Use:

Here is an Ajax Autocomplete sample for the text field with id "query"
<input type="text" name="q" id="query" />

Create an instance of the Autocomplete object. You can have multiple instances on a single page.

Important: Autocomplete must be initialized after DOM has finished loading. Otherwise you will get an error in IE.
var options, a;
jQuery(function(){
options = { serviceUrl:'service/autocomplete.ashx' };
a = $('#query').autocomplete(options);
});

You can add extra options:
var a = $('#query').autocomplete({
serviceUrl:'service/autocomplete.ashx',
minChars:2,
delimiter: /(,|;)\s*/, // regex or character
maxHeight:400,
width:300,
zIndex: 9999,
deferRequestBy: 0, //miliseconds
params: { country:'Yes' }, //aditional parameters
noCache: false, //default is false, set to true to disable caching
// callback function:
onSelect: function(value, data){ alert('You selected: ' + value + ', ' + data); },
// local autosugest options:
lookup: ['January', 'February', 'March', 'April', 'May'] //local lookup values
});

Use lookup option only if you prefer to inject an array of autocompletion options, rather than sending Ajax queries.

Web page that provides data for Ajax Autocomplete, in our case autocomplete.ashx will receive GET request with querystring ?query=Li, and it must return JSON data in the following format:
{
query:'Li',
suggestions:['Liberia','Libyan Arab Jamahiriya','Liechtenstein','Lithuania'],
data:['LR','LY','LI','LT']
}

Notes:
query - original query value
suggestions - comma separated array of suggested values
data (optional) - data array, that contains values for callback function when data is selected.

Styling:

Script generates the following HTML (sample query Li). Active element when you navigate up and down is marked with class "selected". You can style it any way you wish.
<div class="autocomplete-w1">
<div style="width:299px;" id="Autocomplete_1240430421731" class="autocomplete">
<div><strong>Li</strong>beria</div>
<div><strong>Li</strong>byan Arab Jamahiriya</div>
<div><strong>Li</strong>echtenstein</div>
<div class="selected"><strong>Li</strong>thuania</div>
</div>
</div>

Here is style used in the sample above:
.autocomplete-w1 { background:url(img/shadow.png) no-repeat bottom right; position:absolute; top:0px; left:0px; margin:6px 0 0 6px; /* IE6 fix: */ _background:none; _margin:1px 0 0 0; }
.autocomplete { border:1px solid #999; background:#FFF; cursor:default; text-align:left; max-height:350px; overflow:auto; margin:-6px 6px 6px -6px; /* IE6 specific: */ _height:350px; _margin:0; _overflow-x:hidden; }
.autocomplete .selected { background:#F0F0F0; }
.autocomplete div { padding:2px 5px; white-space:nowrap; overflow:hidden; }
.autocomplete strong { font-weight:normal; color:#3399FF; }

If you will use this CSS, please make sure to correct path to the shadow.png image. Image is included in the package. It uses CSS Drop Shadow technique by Sergio Villarreal.

Java History

2011-12-30T22:55:00.001+05:30

Java is a programming language expressly designed for use in the Standalone and Distributed environment of the Internet. Java was designed to have the "look and feel" of the C++ language, It is an OOPS-Object Oriented Programming model. Java can be used to create complete applications that may run on a single computer or be distributed among servers and clients in a network. It can also be used to build a small application module or Applet for use as part of a Web page. Applets make it possible for a Web page user to interact with the page.

Father of Java James Gosling Complete History

2011-12-30T22:10:00.000+05:30

James Gosling Is The Father of the Java:

James A. Gosling, O.C., Ph.D. (born May 19, 1955 near Calgary, Alberta, Canada) is a famous software developer, best known as the father of the Java programming language.

Educational Qualifications of James Gosling:

In 1977, James Gosling received a B.Sc in Computer Science from the University of Calgary. In 1983, he earned a Ph.D in Computer Science from Carnegie Mellon University, and his doctoral thesis was titled "The Algebraic Manipulation of Constraints". While working towards his doctorate, he wrote a version of emacs (gosmacs), and before joining Sun Microsystems he built a multi-processor version of Unix while at Carnegie Mellon University, as well as several compilers and mail systems.

Since 1984, Gosling has been with Sun Microsystems, and is generally known best as the founder of the Java programming language.

Thinking About Java

Implementations In Java:

He is generally credited as the inventor of the Java programming language in 1991. He did the original design of Java and implemented its original compiler and virtual machine. For this achievement he was elected to the United States National Academy of Engineering. He has also made major contributions to several other software systems, such as NeWS and Gosling Emacs. He also cowrote the "bundle" program, a utility thoroughly detailed in Brian Kernighan and Rob Pike's book The Unix Programming Environment.

Java Always Belongs to 'SUCCESS'

More Details visit Wikipedia

Refer FAQ Questions and Improve Your Java Skills

2011-12-30T21:56:00.000+05:30

Refer This Questions and Get the Job...!

1.What is the use of main method?

Main() method is used to start the execution of the program.

2.What is overloading?

Overloading is nothing but having the same name with different parameters.

(or) The same function having different functionality.

3.What is overriding?

Overriding is nothing but having same name and method signature.

It is between parent class and child class. Child class will always overrides parent class.

4.What are the access modifiers?

Public, Private, Protected and Default.

5.What is Method Signature?

Method signature is nothing but (return type of function + function name + no.of arguments).

6.What are the rules we have to follow in overloading?

i)No.of parameters must be different.

ii)The type of parameters must be different
iii)The order of parameters

iv) It will not depend on return type.

7.What are the Secondary Access Modifiers?

Static, abstract, final, transient and volatile.

8.What is Shadowing?

Declaring the same variables of parent class in the subclass is known as Shadowing.

Example : super.x; this.b;

  class ClassName {
    int  a; int  b;
    void setA(int a) {
      a = a; //here, the local variable has closer scope than the instance 
           // variable, so the expression set parameter equal to itself
      this.a = a; // this is the correct way to set the parameter to the 
            //instance variable.
    }
    void setB(int b) {
     this.b = b;
   }
 }

Let's look at another example,

 class ClassName {
    String name = "Instance Var."; 
    void someMethod() { 
       String name ="Local Var."; 
       System.out.println(name);   //Local Var.
       System.out.println(this.name); //Instance Var. 
    } 
  }

9.What are the types of data types in Java?

byte, short, int, float, long, double, char and Boolean

10.Can we call the non static variables into static methods?

No, vice versa is also not possible.

You cannot use a non-static variable in a static method. If this is what you are trying to do:

class ClassName
{
 string someVariable;
 

 static void SomeMethod()
 {
  someVariable = "JavaHari";
 }
}

You cannot do that. However, you can declare the variable static if you need to, like this:

class ClassName
{
 static string someVariable;
 
 static void SomeMethod()
 {
  someVariable = "JavaHari";
 }
}

11.What is the basic difference between the overloading and overriding?

It is necessary to check the method signature in overloading, whereas

it is not necessary in overriding. Method overloading between the same class methods and method overriding is between parent class method and child class method.

12.What is java bytecode?

Bytecode is a highly optimized set of instructions designed to be executed by the java run time system, which is called the Java Virtual Machine (JVM)

13.What is java virtual machine?

JVM is interpreter for the bytecode.

14.What is Encapsulation?

Encapsulation is the mechanism that binds together code and the data it manipulates, and keeps the safe from outside interference and misuse.

15.What is Data Abstraction?

An Abstraction is noting but keeping the data and methods in a single object.

16.What is inheritance?

Inheritance is the process of getting [Base Class futures in to Derived Class] or [Data members & Methods of one class into another class ] is called Inheritance.

17.What are the types of inheritance?

a) Single Level inheritance.

b) Multiple inheritances

c) Multi level inheritance

d) Hybrid inheritance.
e) Hierarchical inheritance.

18.Dose Java supports multiple inheritances?

No. But by using inner Interfaces it is possible.

19. What is polymorphism?

Polymorphism is a feature that the process of representing one from to multiple forms is known as.

20. What is Type Costing?

The conversion of one data type to another data type is known as

Type Costing. It is possible in higher data type to lower.

21. What is the range and width of long?

Range is -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 and the width is 64.

22. What is the range and width of int?

Range is -2,147,483,648 to 2,147,483,647 and width is 32.

23. What is the range and width of short?

Range is -32,768 to 32,767 and width is 16.

24. What is the range and width of byte?

Range is -128 to 127 and width is 8.

25. What is the declaration of an Array?

int Array[] = new int [5];

26. What is a class?

The process of binding data members and the associated methods in a single unit is known as.
[OR]A class is a template for an object.

27. What is an Object?

Object is instance of a class.
Instance is nothing but allocation sufficient memory space to Data members and Methods

28. What are called instance variables?

The data or variables defined within a class are called instance variables.

29. What is a Constructor?

Constructor is used to initialize the object. Constructors have no return type, not even void.

For constructor the class name and method name must be same.

30. What are the types of Constructors?

Constructors are divided into 3 types : I) Default 2) Parameterized 3)Copy Constructor[object]

31. What are the types of explicit constructors?

Default constructors and Parameterized constructors.

32. Where we use the key word 'this'?

'this' is always a reference to the object on which the method was invoked.

33). Can we get the output using Constructors?

No, These are used only for assigning values.

33. What is garbage Collection?

If no reference to an object, that object is assumed to be no longer

needed, and the memory occupied by the object can be reclaimed.

This is known as garbage collection.

34. What is finalize method?

Using finalize method we can define specific actions that will occur

when an object is just about to be reclaimed by the garbage collector.

35. What is call by value and call by reference?

When a simple type is passed to a method, it is done by use of call

by-by-value. Objects are passed call by reference.

36. What is Recursion?

It is a process of defining something in terms of itself.

37. What is recursive?

A method that calls itself is said to be recursive.

38. What is Static?

Static is the key word, which is used to create a member that can be used by itself, without reference to a specific instance. It is a class level variable. It is illegal to refer to any instance variables inside of a static method.

39. Can we refer instance variables inside of a static method?

No. We can't.

40.What is final?

The final prevents its contents from being modified.

41.What is an inner class?
Inner class is a class, which is, defined in side another class.

42. What is an anonymous class?
Anonymous class is a class, which don't have any name.

43. What is super?
Super is used to get the properties of the previous class.

44. What is Dynamic Method Dispatch?
Dynamic method dispatch is the mechanism by which a call to an overridden
function is resolved at run time, rather than at compile time.

45. What is an abstract class?
Restriction of data is called Abstract. We can't create the instance.
These are virtual classes. It is same as interface but we can implement the methods.

46. What is wrapper class?
Wrapper classes are used to represent the primitive data types as objects.

47. Which key word is used to prevent Overriding?
Final

48. What is a package?
A package statement defines a name space in which classes are stored.

49. What is an interface?
It is a task for specific contract. It does not actually define
any implementations. It is not at all a class. It won't allow constructors.

50. What is public?
If we declare it as a public, classes, subclasses within the package
and outside the package, can access it.

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C-Language Aptitude Questions & Answers

2011-07-28T19:29:00.003+05:30

C-Aptitude Questions & Answers

1. void main()

{

int const * p=5;

printf("%d",++(*p));

}

Answer:

Compiler error: Cannot modify a constant value.

Explanation:

p is a pointer to a "constant integer". But we tried to change the value of the "constant integer".

2. main()

{

char s[ ]="man";

int i;

for(i=0;s[ i ];i++)

printf("\n%c%c%c%c",s[ i ],*(s+i),*(i+s),i[s]);

}

Answer:

mmmm

aaaa

nnnn

Explanation:

s[i], *(i+s), *(s+i), i[s] are all different ways of expressing the same idea. Generally array name is the base address for that array. Here s is the base address. i is the index number/displacement from the base address. So, indirecting it with * is same as s[i]. i[s] may be surprising. But in the case of C it is same as s[i].

3. main()

{

float me = 1.1;

double you = 1.1;

if(me==you)

printf("I love U");

else

printf("I hate U");

}

Answer:

I hate U

Explanation:

For floating point numbers (float, double, long double) the values cannot be predicted exactly. Depending on the number of bytes, the precession with of the value represented varies. Float takes 4 bytes and long double takes 10 bytes. So float stores 0.9 with less precision than long double.

Rule of Thumb:

Never compare or at-least be cautious when using floating point numbers with relational operators (== , >, <, <=, >=,!= ) .

4. main()

{

static int var = 5;

printf("%d ",var--);

if(var)

main();

}

Answer:

5 4 3 2 1

Explanation:

When static storage class is given, it is initialized once. The change in the value of a static variable is retained even between the function calls. Main is also treated like any other ordinary function, which can be called recursively.

5. main()

{

int c[ ]={2.8,3.4,4,6.7,5};

int j,*p=c,*q=c;

for(j=0;j<5;j++) {

printf(" %d ",*c);

++q; }

for(j=0;j<5;j++){

printf(" %d ",*p);

++p; }

}

Answer:

2 2 2 2 2 2 3 4 6 5

Explanation:

Initially pointer c is assigned to both p and q. In the first loop, since only q is incremented and not c , the value 2 will be printed 5 times. In second loop p itself is incremented. So the values 2 3 4 6 5 will be printed.

6. main()

{

extern int i;

i=20;

printf("%d",i);

}

Answer:

Linker Error : Undefined symbol '_i'

Explanation:

extern storage class in the following declaration,

extern int i;

specifies to the compiler that the memory for i is allocated in some other program and that address will be given to the current program at the time of linking. But linker finds that no other variable of name i is available in any other program with memory space allocated for it. Hence a linker error has occurred .

7. main()

{

int i=-1,j=-1,k=0,l=2,m;

m=i++&&j++&&k++||l++;

printf("%d %d %d %d %d",i,j,k,l,m);

}

Answer:

0 0 1 3 1

Explanation :

Logical operations always give a result of 1 or 0 . And also the logical AND (&&) operator has higher priority over the logical OR (||) operator. So the expression ‘i++ && j++ && k++’ is executed first. The result of this expression is 0 (-1 && -1 && 0 = 0). Now the expression is 0 || 2 which evaluates to 1 (because OR operator always gives 1 except for ‘0 || 0’ combination- for which it gives 0). So the value of m is 1. The values of other variables are also incremented by 1.

8. main()

{

char *p;

printf("%d %d ",sizeof(*p),sizeof(p));

}

Answer:

1 2

Explanation:

The sizeof() operator gives the number of bytes taken by its operand. P is a character pointer, which needs one byte for storing its value (a character). Hence sizeof(*p) gives a value of 1. Since it needs two bytes to store the address of the character pointer sizeof(p) gives 2.

9. main()

{

int i=3;

switch(i)

{

default:printf("zero");

case 1: printf("one");

break;

case 2:printf("two");

break;

case 3: printf("three");

break;

}

Answer :

three

Explanation :

The default case can be placed anywhere inside the loop. It is executed only when all other cases doesn't match.

10. main()

{

printf("%x",-1<<4);

}

Answer:

fff0

Explanation :

-1 is internally represented as all 1's. When left shifted four times the least significant 4 bits are filled with 0's.The %x format specifier specifies that the integer value be printed as a hexadecimal value.

11. main()

{

char string[]="Hello World";

display(string);

}

void display(char *string)

{

printf("%s",string);

}

Answer:

Compiler Error : Type mismatch in redeclaration of function display

Explanation :

In third line, when the function display is encountered, the compiler doesn't know anything about the function display. It assumes the arguments and return types to be integers, (which is the default type). When it sees the actual function display, the arguments and type contradicts with what it has assumed previously. Hence a compile time error occurs.

12. main()

{

int c=- -2;

printf("c=%d",c);

}

Answer:

c=2;

Explanation:

Here unary minus (or negation) operator is used twice. Same maths rules applies, ie. minus * minus= plus.

Note:

However you cannot give like --2. Because -- operator can only be applied to variables as a decrement operator (eg., i--). 2 is a constant and not a variable.

13. #define int char

main()

{

int i=65;

printf("sizeof(i)=%d",sizeof(i));

}

Answer:

sizeof(i)=1

Explanation:

Since the #define replaces the string int by the macro char

14. main()

{

int i=10;

i=!i>14;

Printf ("i=%d",i);

}

Answer:

i=0

Explanation:

In the expression !i>14 , NOT (!) operator has more precedence than ‘ >’ symbol. ! is a unary logical operator. !i (!10) is 0 (not of true is false). 0>14 is false (zero).

15. #include<stdio.h>

main()

{

char s[]={'a','b','c','\n','c','\0'};

char *p,*str,*str1;

p=&s[3];

str=p;

str1=s;

printf("%d",++*p + ++*str1-32);

}

Answer:

Explanation:

p is pointing to character '\n'. str1 is pointing to character 'a' ++*p. "p is pointing to '\n' and that is incremented by one." the ASCII value of '\n' is 10, which is then incremented to 11. The value of ++*p is 11. ++*str1, str1 is pointing to 'a' that is incremented by 1 and it becomes 'b'. ASCII value of 'b' is 98.

Now performing (11 + 98 – 32), we get 77("M");

So we get the output 77 :: "M" (Ascii is 77).

16. #include<stdio.h>

main()

{

int a[2][2][2] = { {10,2,3,4}, {5,6,7,8} };

int *p,*q;

p=&a[2][2][2];

*q=***a;

printf("%d----%d",*p,*q);

}

Answer:

SomeGarbageValue---1

Explanation:

p=&a[2][2][2] you declare only two 2D arrays, but you are trying to access the third 2D(which you are not declared) it will print garbage values. *q=***a starting address of a is assigned integer pointer. Now q is pointing to starting address of a. If you print *q, it will print first element of 3D array.

17. #include<stdio.h>

main()

{

struct xx

{

int x=3;

char name[]="hello";

};

struct xx *s;

printf("%d",s->x);

printf("%s",s->name);

}

Answer:

Compiler Error

Explanation:

You should not initialize variables in declaration

18. #include<stdio.h>

main()

{

struct xx

{

int x;

struct yy

{

char s;

struct xx *p;

};

struct yy *q;

};

}

Answer:

Compiler Error

Explanation:

The structure yy is nested within structure xx. Hence, the elements are of yy are to be accessed through the instance of structure xx, which needs an instance of yy to be known. If the instance is created after defining the structure the compiler will not know about the instance relative to xx. Hence for nested structure yy you have to declare member.

19. main()

{

printf("\nab");

printf("\bsi");

printf("\rha");

}

Answer:

hai

Explanation:

\n - newline

\b - backspace

\r - linefeed

20. main()

{

int i=5;

printf("%d%d%d%d%d%d",i++,i--,++i,--i,i);

}

Answer:

45545

Explanation:

The arguments in a function call are pushed into the stack from left to right. The evaluation is by popping out from the stack. and the evaluation is from right to left, hence the result.

21. #define square(x) x*x

main()

{

int i;

i = 64/square(4);

printf("%d",i);

}

Answer:

Explanation:

the macro call square(4) will substituted by 4*4 so the expression becomes i = 64/4*4 . Since / and * has equal priority the expression will be evaluated as (64/4)*4 i.e. 16*4 = 64

22. main()

{

char *p="hai friends",*p1;

p1=p;

while(*p!='\0') ++*p++;

printf("%s %s",p,p1);

}

Answer:

ibj!gsjfoet

Explanation:

++*p++ will be parse in the given order

Ø *p that is value at the location currently pointed by p will be taken

Ø ++*p the retrieved value will be incremented

Ø when ; is encountered the location will be incremented that is p++ will be executed

Hence, in the while loop initial value pointed by p is ‘h’, which is changed to ‘i’ by executing ++*p and pointer moves to point, ‘a’ which is similarly changed to ‘b’ and so on. Similarly blank space is converted to ‘!’. Thus, we obtain value in p becomes “ibj!gsjfoet” and since p reaches ‘\0’ and p1 points to p thus p1doesnot print anything.

23. #include <stdio.h>

#define a 10

main()

{

#define a 50

printf("%d",a);

}

Answer:

Explanation:

The preprocessor directives can be redefined anywhere in the program. So the most recently assigned value will be taken.

24. #define clrscr() 100

main()

{

clrscr();

printf("%d\n",clrscr());

}

Answer:

100

Explanation:

Preprocessor executes as a seperate pass before the execution of the compiler. So textual replacement of clrscr() to 100 occurs.The input program to compiler looks like this :

main()

{

100;

printf("%d\n",100);

}

Note:

100; is an executable statement but with no action. So it doesn't give any problem

25. main()

{

printf("%p",main);

}

Answer:

Some address will be printed.

Explanation:

Function names are just addresses (just like array names are addresses).

main() is also a function. So the address of function main will be printed. %p in printf specifies that the argument is an address. They are printed as hexadecimal numbers.

27) main()

{

clrscr();

}

clrscr();

Answer:

No output/error

Explanation:

The first clrscr() occurs inside a function. So it becomes a function call. In the second clrscr(); is a function declaration (because it is not inside any function).

28) enum colors {BLACK,BLUE,GREEN}

main()

{

printf("%d..%d..%d",BLACK,BLUE,GREEN);

return(1);

}

Answer:

0..1..2

Explanation:

enum assigns numbers starting from 0, if not explicitly defined.

29) void main()

{

char far *farther,*farthest;

printf("%d..%d",sizeof(farther),sizeof(farthest));

}

Answer:

4..2

Explanation:

the second pointer is of char type and not a far pointer

30) main()

{

int i=400,j=300;

printf("%d..%d");

}

Answer:

400..300

Explanation:

printf takes the values of the first two assignments of the program. Any number of printf's may be given. All of them take only the first two values. If more number of assignments given in the program,then printf will take garbage values.

31) main()

{

char *p;

p="Hello";

printf("%c\n",*&*p);

}

Answer:

Explanation:

* is a dereference operator & is a reference operator. They can be applied any number of times provided it is meaningful. Here p points to the first character in the string "Hello". *p dereferences it and so its value is H. Again & references it to an address and * dereferences it to the value H.

32) main()

{

int i=1;

while (i<=5)

{

printf("%d",i);

if (i>2)

goto here;

i++;

}

fun()

{

here:

printf("PP");

}

Answer:

Compiler error: Undefined label 'here' in function main

Explanation:

Labels have functions scope, in other words The scope of the labels is limited to functions . The label 'here' is available in function fun() Hence it is not visible in function main.

33) main()

{

static char names[5][20]={"pascal","ada","cobol","fortran","perl"};

int i;

char *t;

t=names[3];

names[3]=names[4];

names[4]=t;

for (i=0;i<=4;i++)

printf("%s",names[i]);

}

Answer:

Compiler error: Lvalue required in function main

Explanation:

Array names are pointer constants. So it cannot be modified.

34) void main()

{

int i=5;

printf("%d",i++ + ++i);

}

Answer:

Output Cannot be predicted exactly.

Explanation:

Side effects are involved in the evaluation of i

35) void main()

{

int i=5;

printf("%d",i+++++i);

}

Answer:

Compiler Error

Explanation:

The expression i+++++i is parsed as i ++ ++ + i which is an illegal combination of operators.

36) #include<stdio.h>

main()

{

int i=1,j=2;

switch(i)

{

case 1: printf("GOOD");

break;

case j: printf("BAD");

break;

}

Answer:

Compiler Error: Constant expression required in function main.

Explanation:

The case statement can have only constant expressions (this implies that we cannot use variable names directly so an error).

Note:

Enumerated types can be used in case statements.

37) main()

{

int i;

printf("%d",scanf("%d",&i)); // value 10 is given as input here

}

Answer:

Explanation:

Scanf returns number of items successfully read and not 1/0. Here 10 is given as input which should have been scanned successfully. So number of items read is 1.

38) #define f(g,g2) g##g2

main()

{

int var12=100;

printf("%d",f(var,12));

}

Answer:

100

39) main()

{

int i=0;

for(;i++;printf("%d",i)) ;

printf("%d",i);

}

Answer:

Explanation:

before entering into the for loop the checking condition is "evaluated". Here it evaluates to 0 (false) and comes out of the loop, and i is incremented (note the semicolon after the for loop).

40) #include<stdio.h>

main()

{

char s[]={'a','b','c','\n','c','\0'};

char *p,*str,*str1;

p=&s[3];

str=p;

str1=s;

printf("%d",++*p + ++*str1-32);

}

Answer:

Explanation:

p is pointing to character '\n'.str1 is pointing to character 'a' ++*p meAnswer:"p is pointing to '\n' and that is incremented by one." the ASCII value of '\n' is 10. then it is incremented to 11. the value of ++*p is 11. ++*str1 meAnswer:"str1 is pointing to 'a' that is incremented by 1 and it becomes 'b'. ASCII value of 'b' is 98. both 11 and 98 is added and result is subtracted from 32.

i.e. (11+98-32)=77("M");

41) #include<stdio.h>

main()

{

struct xx

{

int x=3;

char name[]="hello";

};

struct xx *s=malloc(sizeof(struct xx));

printf("%d",s->x);

printf("%s",s->name);

}

Answer:

Compiler Error

Explanation:

Initialization should not be done for structure members inside the structure declaration

42) #include<stdio.h>

main()

{

struct xx

{

int x;

struct yy

{

char s;

struct xx *p;

};

struct yy *q;

};

}

Answer:

Compiler Error

Explanation:

in the end of nested structure yy a member have to be declared.

43) main()

{

extern int i;

i=20;

printf("%d",sizeof(i));

}

Answer:

Linker error: undefined symbol '_i'.

Explanation:

extern declaration specifies that the variable i is defined somewhere else. The compiler passes the external variable to be resolved by the linker. So compiler doesn't find an error. During linking the linker searches for the definition of i. Since it is not found the linker flags an error.

44) main()

{

printf("%d", out);

}

int out=100;

Answer:

Compiler error: undefined symbol out in function main.

Explanation:

The rule is that a variable is available for use from the point of declaration. Even though a is a global variable, it is not available for main. Hence an error.

45) main()

{

extern out;

printf("%d", out);

}

int out=100;

Answer:

100

Explanation:

This is the correct way of writing the previous program.

46) main()

{

show();

}

void show()

{

printf("I'm the greatest");

}

Answer:

Compier error: Type mismatch in redeclaration of show.

Explanation:

When the compiler sees the function show it doesn't know anything about it. So the default return type (ie, int) is assumed. But when compiler sees the actual definition of show mismatch occurs since it is declared as void. Hence the error.

The solutions are as follows:

1. declare void show() in main() .

2. define show() before main().

3. declare extern void show() before the use of show().

47) main( )

{

int a[2][3][2] = {{{2,4},{7,8},{3,4}},{{2,2},{2,3},{3,4}}};

printf(“%u %u %u %d \n”,a,*a,**a,***a);

printf(“%u %u %u %d \n”,a+1,*a+1,**a+1,***a+1);

}

Answer:

100, 100, 100, 2

114, 104, 102, 3

Explanation:

The given array is a 3-D one. It can also be viewed as a 1-D array.

100 102 104 106 108 110 112 114 116 118 120 122

thus, for the first printf statement a, *a, **a give address of first element . since the indirection ***a gives the value. Hence, the first line of the output.

for the second printf a+1 increases in the third dimension thus points to value at 114, *a+1 increments in second dimension thus points to 104, **a +1 increments the first dimension thus points to 102 and ***a+1 first gets the value at first location and then increments it by 1. Hence, the output.

48) main( )

{

int a[ ] = {10,20,30,40,50},j,*p;

for(j=0; j<5; j++)

{

printf(“%d” ,*a);

a++;

}

p = a;

for(j=0; j<5; j++)

{

printf(“%d ” ,*p);

p++;

}

Answer:

Compiler error: lvalue required.

Explanation:

Error is in line with statement a++. The operand must be an lvalue and may be of any of scalar type for the any operator, array name only when subscripted is an lvalue. Simply array name is a non-modifiable lvalue.

49) main( )

{

static int a[ ] = {0,1,2,3,4};

int *p[ ] = {a,a+1,a+2,a+3,a+4};

int **ptr = p;

ptr++;

printf(“\n %d %d %d”, ptr-p, *ptr-a, **ptr);

*ptr++;

printf(“\n %d %d %d”, ptr-p, *ptr-a, **ptr);

*++ptr;

printf(“\n %d %d %d”, ptr-p, *ptr-a, **ptr);

++*ptr;

printf(“\n %d %d %d”, ptr-p, *ptr-a, **ptr);

}

Answer:

111

222

333

344

Explanation:

Let us consider the array and the two pointers with some address

100 102 104 106 108

100

102

104

106

108

1000 1002 1004 1006 1008

ptr

1000

2000

After execution of the instruction ptr++ value in ptr becomes 1002, if scaling factor for integer is 2 bytes. Now ptr – p is value in ptr – starting location of array p, (1002 – 1000) / (scaling factor) = 1, *ptr – a = value at address pointed by ptr – starting value of array a, 1002 has a value 102 so the value is (102 – 100)/(scaling factor) = 1, **ptr is the value stored in the location pointed by the pointer of ptr = value pointed by value pointed by 1002 = value pointed by 102 = 1. Hence the output of the firs printf is 1, 1, 1.

After execution of *ptr++ increments value of the value in ptr by scaling factor, so it becomes1004. Hence, the outputs for the second printf are ptr – p = 2, *ptr – a = 2, **ptr = 2.

After execution of *++ptr increments value of the value in ptr by scaling factor, so it becomes1004. Hence, the outputs for the third printf are ptr – p = 3, *ptr – a = 3, **ptr = 3.

After execution of ++*ptr value in ptr remains the same, the value pointed by the value is incremented by the scaling factor. So the value in array p at location 1006 changes from 106 10 108,. Hence, the outputs for the fourth printf are ptr – p = 1006 – 1000 = 3, *ptr – a = 108 – 100 = 4, **ptr = 4.

50) main( )

{

char *q;

int j;

for (j=0; j<3; j++) scanf(“%s” ,(q+j));

for (j=0; j<3; j++) printf(“%c” ,*(q+j));

for (j=0; j<3; j++) printf(“%s” ,(q+j));

}

Explanation:

Here we have only one pointer to type char and since we take input in the same pointer thus we keep writing over in the same location, each time shifting the pointer value by 1. Suppose the inputs are MOUSE, TRACK and VIRTUAL. Then for the first input suppose the pointer starts at location 100 then the input one is stored as

M

O

U

When the second input is given the pointer is incremented as j value becomes 1, so the input is filled in memory starting from 101.

M

T

R

A

C

K

\0

The third input starts filling from the location 102

M

T

V

I

R

T

U

A

L

This is the final value stored .

The first printf prints the values at the position q, q+1 and q+2 = M T V

The second printf prints three strings starting from locations q, q+1, q+2

i.e MTVIRTUAL, TVIRTUAL and VIRTUAL.

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What is Unit Testing..?

2011-07-02T12:33:00.000+05:30

What is Unit Testing

Unit Testing...?

An insight of Unit testing reasons to employ unit testing

Unit testing is a method of testing each source code at individual level. The source codes are determined whether they can be freely used or not. Unit testing comes under software development phase that has all small testable portions for applications. Each of these codes are individually scrutinized and made for proper operation. Unit testing can be done manually as well as automated.

Characteristics of unit testing:

1) Unit testing involves is vital to tests that are under unit test.

1) Source code could be modified easily for functioning of program or source code, in unit testing.

2) Unit testing may be time consuming and tedious.

3) Patience and thoroughness is required to be with you when you use unit testing.

4) Documentation need to be maintained in unit testing.

Steps for conducting unit testing

Main purpose of unit testing is to find any errors by conducting tests in program unit test plan. There are several steps required in conducting unit tests:

1) Review program unit: You can use several techniques to carry on review of program unit. It is a necessary step before you start with unit testing. This can be done using static analysis technique like desk check, inspection or structured walk through. You can even use automated static analysis tools to get in to this process.

2) Conducting code execution tests: There are dynamic analysis techniques that you can use in conducting code execution tests. To assist with this process, you can also use automated dynamic tools such as coverage monitors, memory analysis tools etc. In unit testing, test programs are performed one at a time. This helps in identifying errors very easily. This is because you look at all little errors one by one. As soon as coding is complete, program units are tested immediately. It may be necessary to use temporary modules that may be simulating with real modules.

3) Use of drivers and stubs: In unit testing, you need to write drivers and stubs. These driver modules are used to simulate a calling module and then call a unit program that is being tested. They are passed with specific input arguments. Drivers could be written in many ways. You can either prompt them interactively for input arguments or let it accept input programs from a file.

Now, when you want to test the ability of unit that is being tested to another module, it is necessary to make use of another module that is called stub. You may use more than one stub at a time. It depends on total number of program units that are participating in testing. Now, you have many ways of writing stubs too. You can either return control immediately or return a message that indicates its calling and then write back the received inputs.

4) Identification and resolving power of any discrepancies: Here is the step where you compare the actual result to the expected result. If there is no bug then that is recorded as non-discrepant program unit test plan. If there is any kind of error then you need to find them and fix them. if you find error in code then you can use following methods:

1 Isolating cause of error

2 Correction and then recompiling the program

3 Retesting the program again

If there is some error in expected result, then you need to correct that error. Further, re runs the test. As you correct all bugs and errors in unit testing, you must re execute the full unit program. There may be any unit metrics required while checking these and you must list them individually. Later on with use of evaluating test metrics, you can identify methods for gathering these test metrics.

5) Determining completion of test: You find the unit test to be complete when :

1 You have finished executing tests that are itemised in program unit test plan.

2 You are satisfied that the code is able to match the required design.

3 You have finished correcting and re testing of errors.

4 You are documenting the test results in the program unit test plan.

unit testing

Benefits of unit testing

Main aim of unit testing is to isolate all small units of codes and then show that each small part is error free. There are many benefits of unit testing.

1)Simplifies integration: As testing is done in each small unit of code, all similar codes are found to be integrated. At this step, it becomes ready for integration testing.

2)Helps in facilitating change: With the help of unit testing, you can even re factor code at later stage. This will help you to make sure that the code works properly. In this way, there is facilitation in writing test cases. Now, even you can make changes accordingly. With the help of unit testing, you can make changes in code easily.

3)Good documentation: Immediately after doing the unit testing, there is good documentation that is being needed. With unit testing, you are able to identify the characteristics that are making your application to have success.

4)Designing: Unit test plays the role of a rough and formal design that is necessary. This is because each unit test determines design element that is being used for specifying classes, methods and observable behavior.

Application of Unit Testing

1)Unit testing could be used in extreme programming and this relies on unit testing framework.

2)Techniques: With the use of automation techniques, you can help to find the correctness of unit testing.

3)Language level support: Unit testing also help in providing language level unit testing support.

4)Framework supports: Unit testing provides good unit test frameworks that uses assertions, exception handling and all other major things to carry on unit testing.

what-is-unit-testing

Fig: separating database layer in unit testing

Unit testing is the first step of testing and if this is carried out well, it opens your application to move further level of testing and then to success of your application.

How to Install Oracle 9i or 10g Software Installation Picture Help

2011-07-01T10:23:00.000+05:30

How to Install Oracle 10g Installation Picture Help
[ http://java2hari.blogspot.com/ ]

1. Buy/Download Oracle 9i or 10g Software from Oracle Corporation.

2. Click on Oracle Setup icon.

3. Write SID (Source ID) Names

*Global Database Name : Harisid

*Database Password : tiger

4. Click on Next

5. Click on Install.

6. Please Wait at least 5minits.........

7. Click on Icon...

8. Enter SCOTT password as tiger
9. Click on OK

Installation is Successfully Completed
||| Click Here to Download |||

A

2011-03-10T00:30:00.000+05:30

Abstract:

A Java keyword used in a class definition to specify that a class is not to be instantiated, but rather inherited by other classes. An abstract class can have abstract methods that are not implemented in the abstract class, but in subclasses.

Abstract class:

A class that contains one or more abstract methods, and therefore can never be instantiated. Abstract classes are defined so that other classes can extend them and make them concrete by implementing the abstract methods.

Abstract method:

A method that has no implementation.

Abstract Window Toolkit (AWT):

A collection of graphical user interface (GUI) components that were implemented using native-platform versions of the components. These components provide that subset of functionality which is common to all native platforms. Largely supplanted by the Project Swing component set. See also Swing.

Access control:

The methods by which interactions with resources are limited to collections of users or programs for the purpose of enforcing integrity, confidentiality, or availability constraints.

ACID:

The acronym for the four properties guaranteed by transactions: atomicity, consistency, isolation, and durability.

Actual parameter list

The arguments specified in a particular method call. See also formal parameter list.

API:

Application Programming Interface. The specification of how a programmer writing an application accesses the behavior and state of classes and objects.

Applet:

A component that typically executes in a Web browser, but can execute in a variety of other applications or devices that support the applet programming model.

Argument:

A data item specified in a method call. An argument can be a literal value, a variable, or an expression.

Array:

A collection of data items, all of the same type, in which each item's position is uniquely designated by an integer.

ASCII:

American Standard Code for Information Interchange. A standard assignment of 7-bit numeric codes to characters. See also Unicode.

Atomic:

Refers to an operation that is never interrupted or left in an incomplete state under any circumstance.

Authentication:

The process by which an entity proves to another entity that it is acting on behalf of a specific identity.

Authorization:

See access control.

Auto boxing:

Automatic conversion between reference and primitive types.

Hibernate FAQ'S

2011-03-01T23:50:00.000+05:30

HIBERNATE FAQ’S

Q1.what is the advantage of Hibernate over jdbc?

There are so many
1)    Hibernate is data base independent, your code will work for all ORACLE,MySQL ,SQLServer etc.
In case of JDBC query must be data base specific. So hibernate based persistance logic is database independent persistance logic and JDBC based persistance logic is database dependent logic.
2)    As Hibernate is set of Objects ,
3) No need to learn SQL language.You can treat TABLE as a Object . Only Java knowledge is need.
In case of JDBC you need to learn SQL.
3)    Dont need Query tuning in case of Hibernate. If you use Criteria Quires in Hibernate then hibernate automatically tuned your query and return best result with performance.
In case of JDBC you need to tune your queries.
4)     You will get benefit of Cache. Hibernate support two level of cache. First level and 2nd level. So you can store your data into Cache for better performance.
In case of JDBC you need to implement your java cache .
5)    Hibernate supports Query cache and It will provide the statistics about your query and database status.
JDBC Not provides any statistics.
6)    Development fast in case of Hibernate because you dont need to write queries
7)    No need to create any connection pool in case of Hibernate. You can use c3p0.
In case of JDBC you need to write your own connection pool
8)    In the xml file you can see all the relations between tables in case of Hibernate. Easy readability.
9)    You can load your objects on start up using lazy=false in case of Hibernate.
JDBC Dont have such support.
10 ) Hibernate Supports automatic versioning of rows but JDBC Not.

Q2.What is Hibernate?

Hibernate is an open source, light weight Object Relational Mapping tool to develop the database independent persistence login in java and j2ee based applications.
Hibernate is a pure Java object-relational mapping (ORM) and persistence framework that allows you to map plain old Java objects to relational database tables using (XML) configuration and mapping files. Its purpose is to relieve the developer from a significant amount of relational data persistence-related programming tasks
Q3.What is ORM ?

ORM stands for object/relational mapping, means providing the mapping between class with table and member variables with columns is called ORM. ORM is the automated persistence of objects in a Java application to the tables in a relational database.

Q4.hat does ORM consists of ?

An ORM solution consists of the following four pieces:

API for performing basic CRUD operations
API to express queries referring to classes
Facilities to specify metadata
Optimization facilities : dirty checking,lazy associations fetching

Q5.What are the ORM levels ?

The ORM levels are:

Pure relational (stored procedure.)
Light objects mapping (JDBC)
Medium object mapping
Full object Mapping (composition,inheritance, polymorphism, persistence by reachability)

.
Q6.Why do you need ORM tools like hibernate?

The main advantage of ORM like hibernate is that it can develop the database independent persistence logic. Apart from this, ORM provides following benefits:

Improved productivity

High-level object-oriented API
Less Java code to write
No SQL to write

Improved performance

Sophisticated caching
Lazy loading
Eager loading

Improved maintainability

A lot less code to write

Improved portability
ORM framework generates database-specific SQL for you

Q7.What Does Hibernate Simplify?

Hibernate simplifies:

Saving and retrieving your domain objects
Making database column and table name changes
Centralizing pre save and post retrieve logic
Complex joins for retrieving related items
Schema creation from object model

Q8.What is the main difference between Entity Beans and Hibernate ?

1)In Entity Bean at a time we can interact with only one data Base. Where as in Hibernate we can able to establishes the connections to more than One Data Base. Only thing we need to write one more configuration file.

2) EJB need container like Weblogic, WebSphare but hibernate don't nned. It can be run on tomcat.

3) Entity Beans does not support OOPS concepts where as Hibernate does.

4) Hibernate supports multi level cacheing, where as Entity Beans doesn't.

5) In Hibernate C3P0 can be used as a connection pool.

6) Hibernate is container independent. EJB not.

Q9.What are the Core interfaces and classes of Hibernate framework?

The five core interfaces are used in just about every Hibernate application. Using these interfaces, you can store and retrieve persistent objects and control transactions.

Configuration class (org.hibernate.cfg package)
Session interface (org.hibernate package)
SessionFactory interface (org.hibernate package)
Transaction interface (org.hibernate package)
Query and Criteria interfaces (org.hibernate package)

Q10.What is the general flow of Hibernate communication with RDBMS?

The general flow of Hibernate communication with RDBMS is :

Load the Hibernate configuration file and create configuration object. It will automatically load all hbm mapping files because mapping file can be configured in configuration file.
Create session factory from configuration object
Get one session from this session factory
Create HQL Query
Execute query to get list containing Java objects.

Q11.What is the need for Hibernate mapping file?

Hibernate mapping file is used to provides the mapping between java class with table member variables with column names of the table. And also we can configure primary key generation algorithm, relations and so on. Typical mapping file look as follows:

Q12.What are the important tags of hibernate.cfg.xml?

This file can be used to provide the database information like driverclass name, url, database usename, database password, dialect, connection pooling mapping file and so on.
Following are the important tags of hibernate.cfg.xml:

Q13.What role does the Session interface play in Hibernate?

The main runtime interface between a Java application and Hibernate The Session interface is the primary interface used by Hibernate applications. It is a single-threaded, short-lived object representing a conversation between the application and the persistent store. It allows you to create query objects to retrieve persistent objects.
The main function of the Session is to offer create, read and delete operations for instances of mapped entity classes. Instances may exist in one of three states:

Transient: never persistent, not associated with any Session
Persistent: associated with a unique Session
Detached: previously persistent, not associated with any Session

Session session = sessionFactory.openSession();
Session interface role:

Wraps a JDBC connection
Factory for Transaction
Holds a mandatory (first-level) cache of persistent objects, used when navigating the object graph or looking up objects by identifier

Q14.What role does the SessionFactory interface play in Hibernate?

SessionFactorys are immutable. The behaviour of a SessionFactory is controlled by properties supplied at configuration time. These properties are defined on Environment.
The application obtains Session instances from a SessionFactory. There is typically a single SessionFactory for the whole application—created during application initialization. The SessionFactory caches generate SQL statements and other mapping metadata that Hibernate uses at runtime. It also holds cached data that has been read in one unit of work and may be reused in a future unit of work
Implementors must be threadsafe.
SessionFactory sessionFactory = configuration.buildSessionFactory();

Q15.What are the most common ways to specify the Hibernate configuration properties?

The most common methods of Hibernate configuration are:

Programmatic configuration

By using setProperty(-) method of org.hibernate.cfg.Configuration.

XML configuration (hibernate.cfg.xml)
By using .properties file
By Using annotaions.(from Hibernate 3.3 on words)

Q16.How do you map Java Objects with Database tables?

First we need to write Java domain objects (beans with setter and getter).
Write hbm.xml, where we map java class to table and database columns to Java class variables.

Example :
<hibernate-mapping>
<class name="com.durgasoft.EmployeeBean" table="EMPLOYEE">
     <id name=”eid” colume=”id”/>
   <property name="ename" column="NAME" length="255"
     not-null="true" type="java.lang.String"/>
   <property name="address" column="ADDR" length="255"
     not-null="true" type="java.lang.String"/>
</class>
</hibernate-mapping>

Q17.How do you define sequence generated primary key algorithm in hibernate?

By using <id>, <generator> tags we can configure the primary key and primary key generation algorithm.
Example:-
<id name="userid" column="USER_ID" type="java.lang.Long">
<generator class="sequence">
<param name="table">SEQ_NAME</param>
<generator>
</id>

Q18.What is component mapping in Hibernate?

A component is an object saved as a value, not as a reference
A component can be saved directly without needing to declare interfaces or identifier properties
Required to define an empty constructor
Shared references not supported

Q19 . Difference between getCurrentSession() and openSession() in Hibernate ?

getCurrentSession() :
Obtains the current session. The "current session" refers to a Hibernate Session bound by Hibernate behind the scenes, to the transaction scope.
A Session is opened when getCurrentSession() is called for the first time and closed when the transaction ends. It is also flushed automatically before the transaction commits. You can call getCurrentSession() as often and anywhere you want as long as the transaction runs. Only the Session that you obtained with sf.getCurrentSession() is flushed and closed automatically.

openSession() :
If you decide to use manage the Session yourself the go for sf.openSession() , you have to flush() and close() it.
It does not flush and close() automatically.
Example :
Transaction tx =session.berginTransaction();

Session session = factory.openSession();

try {
tx.begin();

// Do some work
session.createQuery(...);
session.persist(...);

session.flush(); // Extra work you need to do

tx.commit();
}
catch (RuntimeException e) {
tx.rollback();
throw e; // or display error message
}
finally {
session.close(); // Extra work you need to do
}

Q20.What are the types of Hibernate instance states ?

Three types of instance states:

Transient -The instance is not associated with any persistence context
Persistent -The instance is associated with a persistence context
Detached -The instance was associated with a persistence context which has been closed – currently not associated

Q21.What are the types of inheritance models in Hibernate?

There are three types of inheritance models in Hibernate:

Table per class hierarchy
Table per subclass
Table per concrete class

Q22.What is Hibernate Query Language (HQL)?

Hibernate Query Language is query language which is used to develop the data independent query language in the application. This HQL queries are not related to any database. Hibernate offers a query language that embodies a very powerful and flexible mechanism to query, store, update, and retrieve objects from a database. This language, the Hibernate query Language (HQL), is an object-oriented extension to SQL.

Q23.What are the ways to express joins in HQL?

HQL provides four ways of expressing (inner and outer) joins:-

An implicit association join
An ordinary join in the FROM clause
A fetch join in the FROM clause.
A theta-style join in the WHERE clause.

Q24 . Transaction with plain JDBC in Hibernate ?

If you don't have JTA and don't want to deploy it along with your application, you will usually have to fall back to JDBC transaction demarcation. Instead of calling the JDBC API you better use Hibernate's Transaction and the built-in session-per-request functionality:

To enable the thread-bound strategy in your Hibernate configuration:

set hibernate.transaction.factory_class to org.hibernate.transaction.JDBCTransactionFactory
set hibernate.current_session_context_class to thread

Session session = factory.openSession();
Transaction tx = null;
try {
tx = session.beginTransaction();

// Do some work
session.load(...);
session.persist(...);

tx.commit(); // Flush happens automatically
}
catch (RuntimeException e) {
tx.rollback();
throw e; // or display error message
}
finally {
session.close();
}

Q25 . What are the general considerations or best practices for defining your Hibernate persistent classes?

1.You must have a default no-argument constructor for your persistent classes and there should be getXXX()and setXXX() methods for all your persistable instance variables.

2.You should implement the equals() and hashCode() methods based on your business key and it is important not to use the id field in your equals() and hashCode() definition if the id field is a surrogate key (i.e. Hibernate managed identifier). This is because the Hibernate only generates and sets the field when saving the object.

3. It is recommended to implement the Serializable interface. This is potentially useful if you want to migrate around a multi-processor cluster.

4.The persistent class should not be final because if it is final then lazy loading cannot be used by creating proxy objects.

Q26 . Difference between session.update() and session.lock() in Hibernate ?

The session.update method is used to update the persistence object in the in the database.
The session.lock() method simply reattaches the object to the session without checking or updating the database on the assumption that the database in sync with the detached object. It is the best practice to use either session.update(..) or session.saveOrUpdate(). Use session.lock() only if you are absolutely sure that the detached object is in sync with your detached object or if it does not matter because you will be overwriting all the columns that would have changed later on within the same transaction.

Q27.What are the Collection types in Hibernate ?

Set
List
Array
Map
Bag

Q28.What is the difference between sorted and ordered collection in hibernate?
sorted collection vs. order collection :-

Sorted Collection	Order Collection
A sorted collection is sorting a collection by utilizing the sorting features provided by the Java collections framework. The sorting occurs in the memory of JVM which running Hibernate, after the data being read from database using java comparator.	Order collection is sorting a collection by specifying the order-by clause for sorting this collection when retrieval.
If your collection is not large, it will be more efficient way to sort it.	If your collection is very large, it will be more efficient way to sort it .

Q29.What are the ways to express joins in HQL?

HQL provides four ways of expressing (inner and outer) joins:-

An implicit association join
An ordinary join in the FROM clause
A fetch join in the FROM clause.
A theta-style join in the WHERE clause.

Q30.What do you mean by Named – SQL query?

Named SQL queries are defined in the mapping xml document and called wherever required.
Example:
<sql-query name = "empdetails">
   <return alias="emp" class="com.durgasoft.Employee"/>
    SELECT emp.EMP_ID AS {emp.empid},
                 emp.EMP_ADDRESS AS {emp.address},
                 emp.EMP_NAME AS {emp.name}
      FROM Employee EMP WHERE emp.NAME LIKE :name
</sql-query>

Invoke Named Query :
List people = session.getNamedQuery("empdetails")
                     .setString("TomBrady", name)
                     .setMaxResults(50)
                     .list();

Q31.How do you invoke Stored Procedures?
<sql-query name="selectAllEmployees_SP" callable="true">
<return alias="emp" class="employee">
   <return-property name="empid" column="EMP_ID"/>
<return-property name="name" column="EMP_NAME"/>
<return-property name="address" column="EMP_ADDRESS"/>
    { ? = call selectAllEmployees() }
</return>
</sql-query>

Q32.Explain Criteria API .?

The interface org.hibernate.Criteria represents a query against a particular persistent class. The Session is a factory for Criteria instances. Criteria is a simplified API for retrieving entities by composing Criterion objects. This is a very convenient approach for functionality like "search" screens where there is a variable number of conditions to be placed upon the result set.
Example :
List employees = session.createCriteria(Employee.class)
                         .add(Restrictions.like("name", "a%") )
                         .add(Restrictions.like("address", "Boston"))
                         .addOrder(Order.asc("name") )
                         .list();

Q33.What’s the difference between load() and get()?

load()	get()
-Only use the load() method if you are sure that the object exists.	-If you are not sure that the object exists, then use one of the get() methods.
-load() method will throw an exception if the unique id is not found in the database.	-get() method will return null if the unique id is not found in the database.
-load() just returns a proxy by default and database won’t be hit until the proxy is first invoked.	-get() will hit the database immediately.

Q34.What is the difference between and merge and update ?

Use update() if you are sure that the session does not contain an already persistent instance with the same identifier, and merge() if you want to merge your modifications at any time without consideration of the state of the session.

Q35.Define cascade and inverse option in one-many mapping?

cascade - enable operations to cascade to child entities.
cascade="all|none|save-update|delete|all-delete-orphan"

inverse - mark this collection as the "inverse" end of a bidirectional association.
inverse="true|false"
Essentially "inverse" indicates which end of a relationship should be ignored, so when persisting a parent who has a collection of children, should you ask the parent for its list of children, or ask the children who the parents are?

Q36.Define HibernateTemplate?

org.springframework.orm.hibernate.HibernateTemplate is a helper class which provides different methods for querying/retrieving data from the database. It also converts checked HibernateExceptions into unchecked DataAccessExceptions.

Q37.What are the benefits does HibernateTemplate provide?

The benefits of HibernateTemplate are :

HibernateTemplate, a Spring Template class simplifies interactions with Hibernate Session.
Common functions are simplified to single method calls.
Sessions are automatically closed.
Exceptions are automatically caught and converted to runtime exceptions.

Q38. How do you switch between relational databases without code changes?

Using Hibernate SQL Dialects , we can switch databases. Hibernate will generate appropriate hql queries based on the dialect defined.

Q39.If you want to see the Hibernate generated SQL statements on console, what should we do?

By using “show_sql” property of the hibernate configuration file
In Hibernate configuration file set as follows:
<property name="show_sql">true</property>

Q40.What are derived properties?

The properties that are not mapped to a column, but calculated at runtime by evaluation of an expression are called derived properties. The expression can be defined using the formula attribute of the element.

Q41.Define cascade and inverse option in one-many mapping?

Q42 . Explain about transaction file?

Transactions denote a work file which can save changes made or revert back the changes. A transaction can be started by session.beginTransaction() and it uses JDBC connection, CORBA or JTA. When this session starts several transactions may occur.

Q43 . Difference between session.save() , session.saveOrUpdate() and session.persist()?

All methods are used to store the data in to database
session.save() : save() method uSave does an insert and will fail if the primary key is already persistent.

session.saveOrUpdate() : saveOrUpdate() insert the data in the database if that primary key data not available and it update the data if primary key data not availabt
session.persist() :it is the same like session.save(). But session.save() return Serializable object but session.persist() return void.
For Example :
         if you do :-
         System.out.println(session.save(question));
         This will print the generated primary key.
         if you do :-
         System.out.println(session.persist(question));
         Compile time error because session.persist() return void.

Q44 . Explain about the id field?

This id field is used to configure the primary key in the mapping file, and also we can configure primary key generation algorithm.

Q45.What is the use of dynamic-insert and dynamic-update attributes in a class mapping?

Criteria is a simplified API for retrieving entities by composing Criterion objects. This is a very convenient approach for functionality like "search" screens where there is a variable number of conditions to be placed upon the result set.

dynamic-update (defaults to false): Specifies that UPDATE SQL should be generated at runtime and contain only those columns whose values have changed
dynamic-insert (defaults to false): Specifies that INSERT SQL should be generated at runtime and contain only the columns whose values are not null.

Q46.What is automatic dirty checking?

Automatic dirty checking is a feature that saves us the effort of explicitly asking Hibernate to update the database when we modify the state of an object inside a transaction.

Q47.What are Callback interfaces?

Callback interfaces allow the application to receive a notification when something interesting happens to an object—for example, when an object is loaded, saved, or deleted. Hibernate applications don't need to implement these callbacks, but they're useful for implementing certain kinds of generic functionality.

Q48.What is Hibernate proxy?

The proxy attribute enables lazy initialization of persistent instances of the class. Hibernate will initially return CGLIB proxies which implement the named interface. The actual persistent object will be loaded when a method of the proxy is invoked.

Q49.How can Hibernate be configured to access an instance variable directly and not through a setter method ?

By mapping the property with access="field" in Hibernate metadata. This forces hibernate to bypass the setter method and access the instance variable directly while initializing a newly loaded object.

Q50.How can a whole class be mapped as immutable?

Mark the class as mutable="false" (Default is true),. This specifies that instances of the class are (not) mutable. Immutable classes, may not be updated or deleted by the application.

Q51 . Explain about transparent persistence of Hibernate?

Transparent persistence is provided for Plain old Java objects or POJOs. For proper functioning of the applications importance should be given to the methods equals () and hash Code methods (). It has a requirement which should be strictly followed in the applications which is a no-argument constructor.

Q52 . Explain about the dirty checking feature of Hibernate?

Dirty checking feature of the Hibernate allows users or developers to avoid time consuming data base write actions. This feature makes necessary updations and changes to the fields which require a change, remaining fields are left unchanged or untouched.

Q53 . What is the effect when a transient mapped object is passed onto a Sessions save?

When a Sessions save () is passed to a transient mapped object it makes the method to become more persistent. Garbage collection and termination of the Java virtual machine stays as long as it is deleted explicitly. It may head back to its transient state.

Q54 . Explain about addClass function?

This function translates a Java class name into file name. This translated file name is then loaded as an input stream from the Java class loader. This addClass function is important if you want efficient usage of classes in your code.

Spring FAQ'S

2011-03-01T23:34:00.000+05:30

SPRING FAQ’S

Q1. What is IOC (or Dependency Injection)?

The basic concept of the Inversion of Control pattern (also known as dependency injection) is that you do not create your objects but describe how they should be created. You don't directly connect your components and services together in code but describe which services are needed by which components in a configuration file. A container (in the case of the Spring framework, the IOC container) is then responsible for hooking it all up.

i.e., Applying IoC, objects are given their dependencies at creation time by some external entity that coordinates each object in the system. That is, dependencies are injected into objects. So, IoC means an inversion of responsibility with regard to how an object obtains references to collaborating objects.

Q2. What are the different types of IOC (dependency injection) ?

There are three types of dependency injection:

v Constructor Injection (e.g. Pico container, Spring etc): Dependencies are provided as constructor parameters.

v Setter Injection (e.g. Spring): Dependencies are assigned through JavaBeans properties (ex: setter methods).

v Interface Injection (e.g. Avalon): Injection is done through an interface.

Note: Spring supports only Constructor and Setter Injection

Q3. What are the benefits of IOC (Dependency Injection)?

Benefits of IOC (Dependency Injection) are as follows:

v Minimizes the amount of code in your application. With IOC containers you do not care about how services are created and how you get references to the ones you need. You can also easily add additional services by adding a new constructor or a setter method with little or no extra configuration.

v Make your application more testable by not requiring any singletons or JNDI lookup mechanisms in your unit test cases. IOC containers make unit testing and switching implementations very easy by manually allowing you to inject your own objects into the object under test.

v Loose coupling is promoted with minimal effort and least intrusive mechanism. The factory design pattern is more intrusive because components or services need to be requested explicitly whereas in IOC the dependency is injected into requesting piece of code. Also some containers promote the design to interfaces not to implementations design concept by encouraging managed objects to implement a well-defined service interface of your own.

v IOC containers support eager instantiation and lazy loading of services. Containers also provide support for instantiation of managed objects, cyclical dependencies, life cycles management, and dependency resolution between managed objects etc.

Q4. What is Spring ?

Spring is an open source framework created to address the complexity of enterprise application development. One of the chief advantages of the Spring framework is its layered architecture, which allows you to be selective about which of its components you use while also providing a cohesive framework for J2EE application development.

Q5. What are the advantages of Spring framework?

The advantages of Spring are as follows:

v Spring has layered architecture. Use what you need and leave you don't need now.

v Spring Enables POJO Programming. There is no behind the scene magic here. POJO programming enables continuous integration and testability.

v Dependency Injection and Inversion of Control Simplifies JDBC

v Open source and no vendor lock-in.

Q6. What are features of Spring ?

Lightweight:
spring is lightweight when it comes to size and transparency. The basic version of spring framework is around 1MB. And the processing overhead is also very negligible.

Inversion of control (IOC):
Loose coupling is achieved in spring using the technique Inversion of Control. The objects give their dependencies instead of creating or looking for dependent objects.

Aspect oriented (AOP):
Spring supports Aspect oriented programming and enables cohesive development by separating application business logic from system services.

Container:
Spring contains and manages the life cycle and configuration of application objects.

MVC Framework:
Spring comes with MVC web application framework, built on core Spring functionality. This framework is highly configurable via strategy interfaces, and accommodates multiple view technologies like JSP, Velocity, Tiles, iText, and POI. But other frameworks can be easily used instead of Spring MVC Framework.

Transaction Management:
Spring framework provides a generic abstraction layer for transaction management. This allowing the developer to add the pluggable transaction managers, and making it easy to demarcate transactions without dealing with low-level issues. Spring's transaction support is not tied to J2EE environments and it can be also used in container less environments.

JDBC Exception Handling:
The JDBC abstraction layer of the Spring offers a meaningful exception hierarchy, which simplifies the error handling strategy. Integration with Hibernate, JDO, and iBATIS: Spring provides best Integration services with Hibernate, JDO and iBATIS
contexts for Web-based applications. As a result, the Spring framework supports integration with Jakarta Struts. The Web module also eases the tasks of handling multi-part requests and binding request parameters to domain objects.

Q7 . What is web module?

This module is built on the application context module, providing a context that is appropriate for web-based applications. This module also contains support for several web-oriented tasks such as transparently handling multipart requests for file uploads and programmatic binding of request parameters to your business objects. It also contains integration support with Jakarta Struts.

Q8. What are the types of Dependency Injection Spring supports?

Setter Injection:
Setter-based DI is realized by calling setter methods on your beans after invoking a no-argument constructor or no-argument static factory method to instantiate your bean.

Constructor Injection:
Constructor-based DI is realized by invoking a constructor with a number of arguments, each representing a collaborator.

Q9. What is Bean Factory ?

A BeanFactory is like a factory class that contains a collection of beans. The BeanFactory holds Bean Definitions of multiple beans within itself and then instantiates the bean whenever asked for by clients.

v BeanFactory is able to create associations between collaborating objects as they are instantiated. This removes the burden of configuration from bean itself and the beans client.

v BeanFactory also takes part in the life cycle of a bean, making calls to custom initialization and destruction methods.

Q10. What is Application Context?

A bean factory is fine to simple applications, but to take advantage of the full power of the Spring framework, you may want to move up to Springs more advanced container, the application context. On the surface, an application context is same as a bean factory.Both load bean definitions, wire beans together, and dispense beans upon request. But it also provides:

v A means for resolving text messages, including support for internationalization.

v A generic way to load file resources.

v Events to beans that are registered as listeners.

Q11. What is the difference between Bean Factory and Application Context ?

On the surface, an application context is same as a bean factory. But application context offers much more..

v Application contexts provide a means for resolving text messages, including support for i18n of those messages.

v Application contexts provide a generic way to load file resources, such as images.

v Application contexts can publish events to beans that are registered as listeners.

v Certain operations on the container or beans in the container, which have to be handled in a programmatic fashion with a bean factory, can be handled declaratively in an application context.

v ResourceLoader support: Spring’s Resource interface us a flexible generic abstraction for handling low-level resources. An application context itself is a ResourceLoader, Hence provides an application with access to deployment-specific Resource instances.

v MessageSource support: The application context implements MessageSource, an interface used to obtain localized messages, with the actual implementation being pluggable

Q12. What are the common implementations of the Application Context ?

The three commonly used implementation of 'Application Context' are

v ClassPathXmlApplicationContext : It Loads context definition from an XML file located in the classpath, treating context definitions as classpath resources. The application context is loaded from the application's classpath by using the code .
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");

v FileSystemXmlApplicationContext : It loads context definition from an XML file in the filesystem. The application context is loaded from the file system by using the code .
ApplicationContext context = new FileSystemXmlApplicationContext("bean.xml");

v XmlWebApplicationContext : It loads context definition from an XML file contained within a web application.

Q13. How is a typical spring implementation look like ?

For a typical Spring Application we need the following files:

v An interface that defines the functions.

v An Implementation that contains properties, its setter and getter methods, functions etc.,

v Spring AOP (Aspect Oriented Programming)

v A XML file called Spring configuration file.

v Client program that uses the function.

Q14. What is the typical Bean life cycle in Spring Bean Factory Container ?

Bean life cycle in Spring Bean Factory Container is as follows:

v The spring container finds the bean’s definition from the XML file and instantiates the bean.

v Using the dependency injection, spring populates all of the properties as specified in the bean definition

v If the bean implements the BeanNameAware interface, the factory calls setBeanName() passing the bean’s ID.

v If the bean implements the BeanFactoryAware interface, the factory calls setBeanFactory(), passing an instance of itself.

v If there are any BeanPostProcessors associated with the bean, their post- ProcessBeforeInitialization() methods will be called.

v If an init-method is specified for the bean, it will be called.

v Finally, if there are any BeanPostProcessors associated with the bean, their postProcessAfterInitialization() methods will be called.

Q15. What do you mean by Bean wiring ?

The act of creating associations between application components (beans) within the Spring container is reffered to as Bean wiring.

Q16. What do you mean by Auto Wiring?

The Spring container is able to autowire relationships between collaborating beans. This means that it is possible to automatically let Spring resolve collaborators (other beans) for your bean by inspecting the contents of the BeanFactory. The autowiring functionality has five modes.

v no

v byName

v byType

v constructor

v autodirect

Q17. What is DelegatingVariableResolver?

Spring provides a custom JavaServer Faces VariableResolver implementation that extends the standard Java Server Faces managed beans mechanism which lets you use JSF and Spring together. This variable resolver is called as DelegatingVariableResolver

Q18. How to integrate Java Server Faces (JSF) with Spring?

JSF and Spring do share some of the same features, most noticeably in the area of IOC services. By declaring JSF managed-beans in the faces-config.xml configuration file, you allow the FacesServlet to instantiate that bean at startup. Your JSF pages have access to these beans and all of their properties.We can integrate JSF and Spring in two ways:

v DelegatingVariableResolver: Spring comes with a JSF variable resolver that lets you use JSF and Spring together.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN"
"http://www.springframework.org/dtd/spring-beans.dtd">

<faces-config>
   <application>
      <variable-resolver>
         org.springframework.web.jsf.DelegatingVariableResolver
      </variable-resolver>
   </application>
</faces-config>

The DelegatingVariableResolver will first delegate value lookups to the default resolver of the underlying JSF implementation, and then to Spring's 'business context' WebApplicationContext. This allows one to easily inject dependencies into one's JSF-managed beans.

v FacesContextUtils: custom VariableResolver works well when mapping one's properties to beans in faces-config.xml, but at times one may need to grab a bean explicitly. The FacesContextUtils class makes this easy. It is similar to WebApplicationContextUtils, except that it takes a FacesContext parameter rather than a ServletContext parameter.

ApplicationContext ctx = FacesContextUtils.getWebApplicationContext(FacesContext.getCurrentInstance());

Q19. What is Java Server Faces (JSF) - Spring integration mechanism?

Spring provides a custom JavaServer Faces VariableResolver implementation that extends the standard JavaServer Faces managed beans mechanism. When asked to resolve a variable name, the following algorithm is performed:

v Does a bean with the specified name already exist in some scope (request, session, application)? If so, return it

v Is there a standard JavaServer Faces managed bean definition for this variable name? If so, invoke it in the usual way, and return the bean that was created.

v Is there configuration information for this variable name in the Spring WebApplicationContext for this application? If so, use it to create and configure an instance, and return that instance to the caller.

v If there is no managed bean or Spring definition for this variable name, return null instead.

v BeanFactory also takes part in the life cycle of a bean, making calls to custom initialization and destruction methods.

As a result of this algorithm, you can transparently use either JavaServer Faces or Spring facilities to create beans on demand.

Q20. What is Significance of JSF- Spring integration ?

Spring - JSF integration is useful when an event handler wishes to explicitly invoke the bean factory to create beans on demand, such as a bean that encapsulates the business logic to be performed when a submit button is pressed.

21. How to integrate your Struts application with Spring?
To integrate your Struts application with Spring, we have two options:

v Configure Spring to manage your Actions as beans, using the ContextLoaderPlugin, and set their dependencies in a Spring context file.

v Subclass Spring's ActionSupport classes and grab your Spring-managed beans explicitly using a getWebApplicationContext() method.

22. What are ORM’s Spring supports ?
Spring supports the following ORM’s :

v Hibernate

v iBatis

v JPA (Java Persistence API)

v TopLink

v JDO (Java Data Objects)

v OJB

23. What are the ways to access Hibernate using Spring ?
There are two approaches to Spring’s Hibernate integration:

v Inversion of Control with a HibernateTemplate and Callback

v Extending HibernateDaoSupport and Applying an AOP Interceptor

24. How to integrate Spring and Hibernate using HibernateDaoSupport?
Spring and Hibernate can integrate using Spring’s SessionFactory called LocalSessionFactory. The integration process is of 3 steps.

v Configure the Hibernate SessionFactory

v Extend your DAO Implementation from HibernateDaoSupport

v Wire in Transaction Support with AOP

25. What are Bean scopes in Spring Framework ?
The Spring Framework supports exactly five scopes (of which three are available only if you are using a web-aware ApplicationContext). The scopes supported are listed below:

Scope	Description
singleton	Scopes a single bean definition to a single object instance per Spring IoC container.
prototype	Scopes a single bean definition to any number of object instances.
request	Scopes a single bean definition to the lifecycle of a single HTTP request; that is each and every HTTP request will have its own instance of a bean created off the back of a single bean definition. Only valid in the context of a web-aware Spring ApplicationContext.
session	Scopes a single bean definition to the lifecycle of a HTTP Session. Only valid in the context of a web-aware Spring ApplicationContext.
global session	Scopes a single bean definition to the lifecycle of a global HTTP Session. Typically only valid when used in a portlet context. Only valid in the context of a web-aware Spring ApplicationContext.

26. What is AOP?
Aspect-oriented programming, or AOP, is a programming technique that allows programmers to modularize crosscutting concerns, or behavior that cuts across the typical divisions of responsibility, such as logging and transaction management. The core construct of AOP is the aspect, which encapsulates behaviors affecting multiple classes into reusable modules.

27. How the AOP used in Spring?
AOP is used in the Spring Framework:To provide declarative enterprise services, especially as a replacement for EJB declarative services. The most important such service is declarative transaction management, which builds on the Spring Framework's transaction abstraction.To allow users to implement custom aspects, complementing their use of OOP with AOP.

28. What do you mean by Aspect ?
A modularization of a concern that cuts across multiple objects. Transaction management is a good example of a crosscutting concern in J2EE applications. In Spring AOP, aspects are implemented using regular classes (the schema-based approach) or regular classes annotated with the @Aspect annotation (@AspectJ style).

29. What do you mean by JointPoint?
A point during the execution of a program, such as the execution of a method or the handling of an exception. In Spring AOP, a join point always represents a method execution.

30. What do you mean by Advice?
Action taken by an aspect at a particular join point. Different types of advice include "around," "before" and "after" advice. Many AOP frameworks, including Spring, model an advice as an interceptor, maintaining a chain of interceptors "around" the join point.

31. What are the types of Advice?
Types of advice:

v Before advice: Advice that executes before a join point, but which does not have the ability to prevent execution flow proceeding to the join point (unless it throws an exception).

v After returning advice: Advice to be executed after a join point completes normally: for example, if a method returns without throwing an exception.

v After throwing advice: Advice to be executed if a method exits by throwing an exception.

v After (finally) advice: Advice to be executed regardless of the means by which a join point exits (normal or exceptional return).

v Around advice: Advice that surrounds a join point such as a method invocation. This is the most powerful kind of advice. Around advice can perform custom behavior before and after the method invocation. It is also responsible for choosing whether to proceed to the join point or to shortcut the advised method execution by returning its own return value or throwing an exception

32. What are the types of the transaction management Spring supports ?
Spring Framework supports:

v Programmatic transaction management.

v Declarative transaction management.

33. What are the benefits of the Spring Framework transaction management ?
The Spring Framework provides a consistent abstraction for transaction management that delivers the following benefits:

v Provides a consistent programming model across different transaction APIs such as JTA, JDBC, Hibernate, JPA, and JDO.

v Supports declarative transaction management.

v Provides a simpler API for programmatic transaction management than a number of complex transaction APIs such as JTA.

v Integrates very well with Spring's various data access abstractions.

34. Why most users of the Spring Framework choose declarative transaction management ?
Most users of the Spring Framework choose declarative transaction management because it is the option with the least impact on application code, and hence is most consistent with the ideals of a non-invasive lightweight container.

35. Explain the similarities and differences between EJB CMT and the Spring Framework's declarative transaction
       management ?
   The basic approach is similar: it is possible to specify transaction behavior (or lack of it) down to individual method level. It is
    possible to make a setRollbackOnly() call within a transaction context if necessary. The differences are:

v Unlike EJB CMT, which is tied to JTA, the Spring Framework's declarative transaction management works in any environment. It can work with JDBC, JDO, Hibernate or other transactions under the covers, with configuration changes only.

v The Spring Framework enables declarative transaction management to be applied to any class, not merely special classes such as EJBs.

v The Spring Framework offers declarative rollback rules: this is a feature with no EJB equivalent. Both programmatic and declarative support for rollback rules is provided.

v The Spring Framework gives you an opportunity to customize transactional behavior, using AOP. With EJB CMT, you have no way to influence the container's transaction management other than setRollbackOnly().

v The Spring Framework does not support propagation of transaction contexts across remote calls, as do high-end application servers.

36. What are object/relational mapping integration module?

Spring also supports for using of an object/relational mapping (ORM) tool over straight JDBC by providing the ORM module. Spring provide support to tie into several popular ORM frameworks, including Hibernate, JDO, and iBATIS SQL Maps. Spring’s transaction management supports each of these ORM frameworks as well as JDBC.

37. When to use programmatic and declarative transaction management ?
Programmatic transaction management is usually a good idea only if you have a small number of transactional operations.
On the other hand, if your application has numerous transactional operations, declarative transaction management is usually worthwhile. It keeps transaction management out of business logic, and is not difficult to configure.

38. Explain about the Spring DAO support ?
The Data Access Object (DAO) support in Spring is aimed at making it easy to work with data access technologies like JDBC, Hibernate or JDO in a consistent way. This allows one to switch between the persistence technologies fairly easily and it also allows one to code without worrying about catching exceptions that are specific to each technology.

39. What are the exceptions thrown by the Spring DAO classes ?
Spring DAO classes throw exceptions which are subclasses of DataAccessException(org.springframework.dao.DataAccessException).Spring provides a convenient translation from technology-specific exceptions like SQLException to its own exception class hierarchy with the DataAccessException as the root exception. These exceptions wrap the original exception.

40. What is SQLExceptionTranslator ?
SQLExceptionTranslator, is an interface to be implemented by classes that can translate between SQLExceptions and Spring's own data-access-strategy-agnostic org.springframework.dao.DataAccessException.

41. What is Spring's JdbcTemplate ?
Spring's JdbcTemplate is central class to interact with a database through JDBC. JdbcTemplate provides many convenience methods for doing things such as converting database data into primitives or objects, executing prepared and callable statements, and providing custom database error handling.
JdbcTemplate template = new JdbcTemplate(myDataSource);

42. What is PreparedStatementCreator ?
PreparedStatementCreator:

v Is one of the most common used interfaces for writing data to database.

v Has one method – createPreparedStatement(Connection)

v Responsible for creating a PreparedStatement.

v Does not need to handle SQLExceptions.

43. What is SQLProvider ?
SQLProvider:

v Has one method – getSql()

v Typically implemented by PreparedStatementCreator implementers.

v Useful for debugging.

44. What is RowCallbackHandler ?
The RowCallbackHandler interface extracts values from each row of a ResultSet.

v Has one method – processRow(ResultSet)

v Called for each row in ResultSet.

v Typically stateful.

45. What are the differences between EJB and Spring ?

Spring and EJB feature comparison.

Feature	EJB	Spring
Transaction management	ü Must use a JTA transaction manager. ü Supports transactions that span remote method calls.	ü Supports multiple transaction environments through its PlatformTransactionManager interface, including JTA, Hibernate, JDO, and JDBC. ü Does not natively support distributed transactions—it must be used with a JTA transaction manager.
Declarative transaction support	ü Can define transactions declaratively through the deployment descriptor. ü Can define transaction behavior per method or per class by using the wildcard character *. ü Cannot declaratively define rollback behavior—this must be done programmatically.	ü Can define transactions declaratively through the Spring configuration file or through class metadata. ü Can define which methods to apply transaction behavior explicitly or by using regular expressions. ü Can declaratively define rollback behavior per method and per exception type.
Persistence	Supports programmatic bean-managed persistence and declarative container managed persistence.	Provides a framework for integrating with several persistence technologies, including JDBC, Hibernate, JDO, and iBATIS.
Declarative security	ü Supports declarative security through users and roles. The management and implementation of users and roles is container specific. ü Declarative security is configured in the deployment descriptor.	ü No security implementation out-of-the box. ü Acegi, an open source security framework built on top of Spring, provides declarative security through the Spring configuration file or class metadata.
Distributed computing	Provides container-managed remote method calls.	Provides proxying for remote calls via RMI, JAX-RPC, and web services.

46 . Do I need any other SOAP framework to run Spring Web Services?

You don't need any other SOAP framework to use Spring Web services, though it can use

some of the features of Axis 1 and 2.

47 . I get NAMESPACE_ERR exceptions when using Spring-WS. What can I do about it?
If you get the following Exception:
NAMESPACE_ERR: An attempt is made to create or change an object in a way which is incorrect with regard to namespaces.

Most often, this exception is related to an older version of Xalan being used. Make sure to upgrade to 2.7.0.

48 .Does Spring-WS run under Java 1.3?
Spring Web Services requires Java 1.4 or higher.

49. Does Spring-WS work under Java 1.4?
Spring Web Services works under Java 1.4, but it requires some effort to make it work. Java 1.4 is bundled with the older XML parser Crimson, which does not handle namespaces correctly. Additionally, it is bundled with an older version of Xalan, which also has problems. Unfortunately, placing newer versions of these on the class path does not override them. .
The only solution that works is to add newer versions of Xerces and Xalan in the lib/endorsed directory of your JDK, as explained in those FAQs (i.e.$JAVA_HOME/lib/endorsed). The following libraries are known to work with Java 1.4.2:

Library	Version
Xerces	2.8.1
Xalan	2.7.0
XML-APIs	1.3.04
SAAJ	1.2

If you want to use WS-Security, note that the XwsSecurityInterceptor requires Java 5, because an underlying library (XWSS) requires it. Instead, you can use the Wss4jSecurityInterceptor.

50 .Does Spring-WS work under Java 1.6?
Java 1.6 ships with SAAJ 1.3, JAXB 2.0, and JAXP 1.4 (a custom version of Xerces and Xalan). Overriding these libraries by putting different version on the classpath will result in various classloading issues, or exceptions in org.apache.xml.serializer.ToXMLSAXHandler. The only option for using more recent versions is to put the newer version in the endorsed directory (see above).

51 . Why do the Spring-WS unit tests fail under Mac OS X?
For some reason, Apple decided to include a Java 1.4 compatibility jar with their JDK 1.5. This jar includes the XML parsers which were included in Java 1.4. No other JDK distribution does this, so it is unclear what the purpose of this compatibility jar is.
The jar can be found at /System/Library/Frameworks/JavaVM.framework/Versions/1.5.0/Classes/.compatibility/14compatibility.jar. You can safely remove or rename it, and the tests will run again.

52 . What is SAAJ?
SAAJ is the SOAP with Attachments API for Java. Like most Java EE libraries, it consists of a set of interfaces (saaj-api.jar), and implementations (saaj-impl.jar). When running in a Application Server, the implementation is typically provided by the application server. Previously, SAAJ has been part of JAXM, but it has been released as a seperate API as part of the , and also as part of J2EE 1.4. SAAJ is generally known as the packagejavax.xml.soap.
Spring-WS uses this standard SAAJ library to create representations of SOAP messages. Alternatively, it can use

53 . What version of SAAJ does my application server support?

Application Server		SAAJ Version
BEA WebLogic 8		1.1
BEA WebLogic 9		1.1/1.2*
BEA WebLogic 10		1.3**
IBM WebSphere 6		1.2
SUN Glassfish 1		1.3
JBoss 4.2		1.3***

54 .I get a NoSuchMethodError when using SAAJ. What can I do about it?
If you get the following stack trace:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.ws.soap.saaj.SaajSoapMessageFactory' defined in ServletContext resource [/WEB-INF/springws-servlet.xml]:
Invocation of init method failed;
nested exception is java.lang.NoSuchMethodError:
javax.xml.soap.MessageFactory.newInstance(Ljava/lang/String;)Ljavax/xml/soap/MessageFactory;
Caused by:
java.lang.NoSuchMethodError:
javax.xml.soap.MessageFactory.newInstance(Ljava/lang/String;)Ljavax/xml/soap/MessageFactory;

Like most J2EE libraries, SAAJ consists of two parts: the API that consists of interfaces (saaj-api.jar) and the implementation (saaj-impl.jar). The stack trace is due to the fact that you are using a new version of the API (SAAJ 1.3), while your application server provides an earlier version of the implementation (SAAJ 1.2 or even 1.1). Spring-WS supports all three versions of SAAJ (1.1 through 1.3), but things break when it sees the 1.3 API, while there is no 1.3 implementation.
The solution therefore is quite simple: to remove the newer 1.3 version of the API, from the class path, and replace it with the version supported by your application server.

55 . I get an UnsupportedOperationException "This class does not support SAAJ 1.1" when I use SAAJ under WebLogic 9. What can I do about it?
WebLogic 9 has a known bug in the SAAJ 1.2 implementation: it implement all the 1.2 interfaces, but throws UnsupportedOperationExceptions when you call them. Confusingly, the exception message is This class does not support SAAJ 1.1, even though it supports SAAJ 1.1 just fine; it just doesn't support SAAJ 1.2. See alsot
Spring-WS has a workaround for this, we basically use SAAJ 1.1 only when dealing with WebLogic 9. Unfortunately, other frameworks which depend on SAAJ, such as XWSS, do not have this workaround. These frameworks happily call SAAJ 1.2 methods, which throw this exception.
The solution is to not use BEA's version of SAAJ, but to use another implementation, like the one from Axis 1, or SUN. In you application context, use the following:
<bean id="messageFactory" class="org.springframework.ws.soap.saaj.SaajSoapMessageFactory">
    <property name="messageFactory">
        <bean class="com.sun.xml.messaging.saaj.soap.MessageFactoryImpl"/>
    </property>
</bean>

56 . I get an UnsupportedOperationException "This class does not support SAAJ 1.1" when I use SAAJ under WebLogic 10. What can I do about it?
Weblogic 10 ships with two SAAJ implementations. By default the buggy 9.x implementation is used (which lives in the package weblogic.webservice.core.soap), but there is a new implementation, which supports SAAJ 1.3 (which lives in the package weblogic.xml.saaj). By looking at the DEBUG logging when Spring Web Services starts up, you can see which SAAJ implementation is used.
To use this new version, you have to create a message factory bean like so:
<bean id="messageFactory" class="org.springframework.ws.soap.saaj.SaajSoapMessageFactory">
    <property name="messageFactory">
        <bean class="weblogic.xml.saaj.MessageFactoryImpl"/>
    </property>
</bean>

57 . I get an IndexOutOfBoundsException when I use SAAJ under JBoss. What can I do about it?
The SAAJ implementation provided by JBoss has some issues. The solution is therefore not to use the JBoss implementation, but to use another implementation. For instance, you can use SUN's reference implementation like so:
<bean id="messageFactory" class="org.springframework.ws.soap.saaj.SaajSoapMessageFactory">
    <property name="messageFactory">
        <bean class="com.sun.xml.messaging.saaj.soap.ver1_1.SOAPMessageFactory1_1Impl"/>
    </property>
</bean>

58 . Does Spring-WS run on IBM WebSphere?
WebSphere bundles some libraries which are out-of-date, and need to be upgraded with more recent versions. Specifically, this includes XML-apis, Xerces, Xalan, and WSDL4J.
There are a couple of ways to upgrade these libraries, all using parent-last or application-first classloading.

v Package the libraries as part of the WAR (in WEB-INF/lib), and run the web application with the parent-last (application-first) classloading.

v Package the libraries as part of the EAR, add class-path entries to the manifest of the web application, and run the entire application with the parent-last classloading.

v Create a new classloader in the WebSphere console, and associate the libraries with. Set this classloader to parent-last.

The last approach has the advantage of restricting the parent-last classloading to the conflicting libraries only, and not to the entire application.

59. Why does Spring-WS only support contract-first?
Note that Spring-WS only requires you to write the XSD; the WSDL can be generated from that.

60 . How do I retrieve the WSDL from a Service?
The &WSDL query parameter does not work.
The &WSDL query parameter is a way to get a WSDL of a class. In SWS, a service is generally not implemented as a single class, but as a collection of endpoints.
There are two ways to expose a WSDL:

v Simply add the WSDL to the root of the WAR, and the file is served normally. This has the disadvantage that the "location" attribute in the WSDL is static, i.e. it does not necessarily reflect the host name of the server. You can transform locations by using a WsdlDefinitionHandlerAdapter.

v Use theMessageDispatcherServlet, which is done is the samples. Every WsdlDefinition listed in the *-servlet.xml will be exposed under the bean name. So if you define a WsdlDefinition namedecho, it will be exposed as echo.wsdl (i.e.http://localhost:8080/echo/echo.wsdl).

61 What is web module?

Spring comes with a full-featured MVC framework for building web applications. Although Spring can easily be integrated with other MVC frameworks, such as Struts, Spring’s MVC framework uses IoC to provide for a clean separation of controller logic from business objects. It also allows you to declaratively bind request parameters to your business objects. It also can take advantage of any of Spring’s other services, such as I18N messaging and validation.

62 What is a BeanFactory?

A BeanFactory is an implementation of the factory pattern that applies Inversion of Control to separate the application’s configuration and dependencies from the actual application code.

63 What is AOP Alliance?

AOP Alliance is an open-source project whose goal is to promote adoption of AOP and interoperability among different AOP implementations by defining a common set of interfaces and components.

64 What is Spring configuration file?

Spring configuration file is an XML file. This file contains the classes information and describes how these classes are configured and introduced to each other.

65 .What does a simple spring application contain?

These applications are like any Java application. They are made up of several classes, each performing a specific purpose within the application. But these classes are configured and introduced to each other through an XML file. This XML file describes how to configure the classes, known as theSpring configuration file.

66 What is XMLBeanFactory?
BeanFactory has many implementations in Spring. But one of the most useful one is org.springframework.beans.factory.xml.XmlBeanFactory, which loads its beans based on the definitions contained in an XML file. To create an XmlBeanFactory, pass a java.io.InputStream to the constructor. The InputStream will provide the XML to the factory. For example, the following code snippet uses a java.io.FileInputStream to provide a bean definition XML file to XmlBeanFactory.

BeanFactory factory = new XmlBeanFactory(new FileInputStream("beans.xml"));
To retrieve the bean from a BeanFactory, call the getBean() method by passing the name of the bean you want to retrieve.

MyBean myBean = (MyBean) factory.getBean("myBean")

67 . What are important ApplicationContext implementations in spring framework?

v ClassPathXmlApplicationContext – This context loads a context definition from an XML file located in the class path, treating context definition files as class path resources.

v FileSystemXmlApplicationContext – This context loads a context definition from an XML file in the filesystem.

v XmlWebApplicationContext – This context loads the context definitions from an XML file contained within a web application.

68 . Explain Bean lifecycle in Spring framework?

v The spring container finds the bean’s definition from the XML file and instantiates the bean.

v Using the dependency injection, spring populates all of the properties as specified in the bean definition.

v If the bean implements the BeanNameAware interface, the factory calls setBeanName() passing the bean’s ID.

v If the bean implements the BeanFactoryAware interface, the factory calls setBeanFactory(), passing an instance of itself.

v If there are any BeanPostProcessors associated with the bean, their post- ProcessBeforeInitialization() methods will be called.

v If an init-method is specified for the bean, it will be called.

v Finally, if there are any BeanPostProcessors associated with the bean, their postProcessAfterInitialization() methods will be called.

69 What is bean wiring?
Combining together beans within the Spring container is known as bean wiring or wiring. When wiring beans, you should tell the container what beans are needed and how the container should use dependency injection to tie them together.

70 How do add a bean in spring application?

        <?xml version="1.0" encoding="UTF-8"?>
       <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
        <beans>
                <bean id="foo" class="com.act.Foo"/>
                <bean id="bar" class="com.act.Bar"/>
        </beans>

71. What are singleton beans and how can you create prototype beans?

Beans defined in spring framework are singleton beans. There is an attribute in bean tag named ‘singleton’ if specified true then bean becomes singleton and if set to false then the bean becomes a prototype bean. By default it is set to true. So, all the beans in spring framework are by default singleton beans.

72 . What are the important beans lifecycle methods?

There are two important bean lifecycle methods. The first one is setup which is called when the bean is loaded in to the container. The second method is the teardown method which is called when the bean is unloaded from the container.

73 . How can you override beans default lifecycle methods?

The bean tag has two more important attributes with which you can define your own custom initialization and destroy methods. Here I have shown a small demonstration. Two new methods fooSetup and fooTeardown are to be added to your Foo class.

74 . What are Inner Beans?

When wiring beans, if a bean element is embedded to a property tag directly, then that bean is said to the Inner Bean. The drawback of this bean is that it cannot be reused anywhere else.

75. What are the different types of bean injections?

There are two types of bean injections.

v By setter

v By constructor

76. What is Auto wiring?

You can wire the beans as you wish. But spring framework also does this work for you. It can auto wire the related beans together. All you have to do is just set the autowire attribute of bean tag to an autowire type.

77 . What are different types of Autowire types?

There are four different types by which autowiring can be done.

v byName

v byType

v constructor

v autodetect

78. What are the different types of events related to Listeners?

There are a lot of events related to ApplicationContext of spring framework. All the events are subclasses of org.springframework.context.Application-Event. They are

v ContextClosedEvent – This is fired when the context is closed.

v ContextRefreshedEvent – This is fired when the context is initialized or refreshed.

v RequestHandledEvent – This is fired when the web context handles any request.

79. What is an Aspect?

An aspect is the cross-cutting functionality that you are implementing. It is the aspect of your application you are modularizing. An example of an aspect is logging. Logging is something that is required throughout an application. However, because applications tend to be broken down into layers based on functionality, reusing a logging module through inheritance does not make sense. However, you can create a logging aspect and apply it throughout your application using AOP.

80 . What is a Jointpoint?

A joinpoint is a point in the execution of the application where an aspect can be plugged in. This point could be a method being called, an exception being thrown, or even a field being modified. These are the points where your aspect’s code can be inserted into the normal flow of your application to add new behavior.

81 What is an Advice?

Advice is the implementation of an aspect. It is something like telling your application of a new behavior. Generally, and advice is inserted into an application at joinpoints.

82 What is a Pointcut?

A pointcut is something that defines at what joinpoints an advice should be applied. Advices can be applied at any joinpoint that is supported by the AOP framework. These Pointcuts allow you to specify where theadvice can be applied.

83 What is an Introduction in AOP?

An introduction allows the user to add new methods or attributes to an existing class. This can then be introduced to an existing class without having to change the structure of the class, but give them the new behavior and state.

84 What is a Target?

A target is the class that is being advised. The class can be a third party class or your own class to which you want to add your own custom behavior. By using the concepts of AOP, the target class is free to center on its major concern, unaware to any advice that is being applied.

85 . What is a Proxy?

A proxy is an object that is created after applying advice to a target object. When you think of client objects the target object and the proxy object are the same.

86 .What is meant by Weaving?

The process of applying aspects to a target object to create a new proxy object is called as Weaving. The aspects are woven intothe target object at the specified joinpoints.

87 What are the different points where weaving can be applied?

v Compile Time

v Classload Time

v Runtime

Q88 . What are the different advice types in spring?

v Around : Intercepts the calls to the target method

v Before : This is called before the target method is invoked

v After : This is called after the target method is returned

v Throws : This is called when the target method throws and exception

v Around : org.aopalliance.intercept.MethodInterceptor

v Before : org.springframework.aop.BeforeAdvice

v After : org.springframework.aop.AfterReturningAdvice

v Throws : org.springframework.aop.ThrowsAdvice

Q89 What are the different types of AutoProxying?

v BeanNameAutoProxyCreator

v DefaultAdvisorAutoProxyCreator

v Metadata autoproxying

Q90 What kind of exceptions those spring DAO classes throw?

The springâ€™s DAO class does not throw any technology related exceptions such as SQLException. They throw exceptions which are subclasses of DataAccessException.

Q91 What is DataAccessException?

DataAccessException is a RuntimeException. This is an Unchecked Exception. The user is not forced to handle these kinds of exceptions.

Q92 How can you configure a bean to get DataSource from JNDI?

        <bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
             <property name="jndiName">
               <value>java:comp/env/jdbc/myDatasource</value>
            </property>
        </bean>

Q93 How can you create a DataSource connection pool?

        <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
           <property name="driver">
               <value>${db.driver}</value>
           </property>
           <property name="url">
              <value>${db.url}</value>
           </property>
           <property name="username">
             <value>${db.username}</value>
           </property>
           <property name="password">
            <value>${db.password}</value>
           </property>
        </bean>

Q94 How JDBC can be used more efficiently in spring framework?

JDBC can be used more efficiently with the help of a template class provided by spring framework called as JdbcTemplate.

Q95 How JdbcTemplate can be used?

With use of Spring JDBC framework the burden of resource management and error handling is reduced a lot. So it leaves developers to write the statements and queries to get the data to and from the database.

JdbcTemplate template = new JdbcTemplate(myDataSource);
A simple DAO class looks like this.

public class StudentDaoJdbc implements StudentDao {
private JdbcTemplate jdbcTemplate;

        public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
           this.jdbcTemplate = jdbcTemplate;
        }
        more..
        }
The configuration is shown below.

Q96 How do you write data to backend in spring using JdbcTemplate?

The JdbcTemplate uses several of these callbacks when writing data to the database. The usefulness you will find in each of these interfaces will vary. There are two simple interfaces. One is PreparedStatementCreator and the other interface is BatchPreparedStatementSetter.

Q97 Explain about PreparedStatementCreator?

PreparedStatementCreator is one of the most common used interfaces for writing data to database. The interface has one method createPreparedStatement().

PreparedStatement createPreparedStatement(Connection conn) throws SQLException;
When this interface is implemented, we should create and return a PreparedStatement from the Connection argument, and the exception handling is automatically taken care off. When this interface is implemented, another interface SqlProvider is also implemented which has a method called getSql() which is used to provide sql strings to JdbcTemplate.

Q98 Explain about BatchPreparedStatementSetter?

If the user what to update more than one row at a shot then he can go for BatchPreparedStatementSetter. This interface provides two methods

        setValues(PreparedStatement ps, int i) throws SQLException;

        int getBatchSize();
The getBatchSize() tells the JdbcTemplate class how many statements to create. And this also determines how many times setValues() will be called.

Q99. Explain about RowCallbackHandler and why it is used?

In order to navigate through the records we generally go for ResultSet. But spring provides an interface that handles this entire burden and leaves the user to decide what to do with each row. The interface provided by spring is RowCallbackHandler. There is a method processRow() which needs to be implemented so that it is applicable for each and everyrow.

void processRow(java.sql.ResultSet rs);

Q100 What is JDBC abstraction and DAO module?

Using this module we can keep up the database code clean and simple, and prevent problems that result from a failure to close database resources. A new layer of meaningful exceptions on top of the error messages given by several database servers is bought in this module. In addition, this module uses Spring’s AOP module to provide transaction management services for objects in a Spring application.

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Struts FAQ'S

2011-03-01T22:38:00.000+05:30

STRUTS FAQ’S

Q1. What is MVC?

Model-View-Controller (MVC) is a design pattern put together to help control change. MVC decouples interface from business logic and data.
Model: The model contains the core of the application's functionality. The model enca psulates the state of the application. Sometimes the only functionality it contains is state. It knows nothing about the view or controller.
View: The view provides the presentation of the model. It is the look of the application. The view can access the model getters, but it has no knowledge of the setters. In addition, it knows nothing about the controller. The view should be notified when changes to the model occur.
Controller: The controller reacts to the user input. It creates and sets the model.

Q2. What is a framework?

Framework is made up of the set of classes which allow us to use a library in a best possible way for a specific requirement.

Q3. What is Struts framework?

Struts framework is an open-source framework for developing the web applications in Java EE, based on MVC-2 architecture. It uses and extends the Java Servlet API. Struts is robust architecture and can be used for the development of application
of any size. Struts framework makes it much easier to design scalable, reliable Web applications with Java. Struts provides its own Controller component and integrates with other technologies to provide the Model and the View. For the Model, Struts can interact with standard data access technologies, like JDBC and EJB, as well as most any third-party packages, like Hibernate, iBATIS, or Object Relational Bridge. For the View, Struts works well with JavaServer Pages, including JSTL and JSF, as well as Velocity Templates, XSLT, and other presentation systems.

Q4. What is Jakarta Struts Framework?

Jakarta Struts is open source implementation of MVC (Model-View-Controller) pattern for the development of web based applications. Jakarta Struts is robust architecture and can be used for the development of application of any size. Struts framework makes it much easier to design scalable, reliable Web applications with Java.

Q5. What is ActionServlet?

The class org.apache.struts.action.ActionServlet is the called the ActionServlet. In the the Jakarta Struts Framework this class plays the role of controller. All the requests to the server
goes through the controller. Controller is responsible for handling all the requests.

Q6. What is role of ActionServlet?

ActionServlet performs the role of Controller:

Process user requests
Determine what the user is trying to achieve according to the request
Pull data from the model (if necessary) to be given to the appropriate view,
Select the proper view to respond to the user
Delegates most of this grunt work to Action classes
Is responsible for initialization and clean-up of resources

Q7. What is Action Class?

Any java class which extends from org.apache.struts.action.Action is called Action class. The Action is part of the controller. The purpose of Action Class is to translate the HttpServletRequest to the business logic. To use the Action, we need to Subclass and overwrite the execute() method. The ActionServlet (commad) passes the parameterized class to Action Form using the execute() method. There should be no database interactions in the action. The action should receive the request, call business objects (which then handle database, or interface with J2EE, etc) and then determine where to go next. Even better, the business objects could be handed to the action at runtime (IoC style) thus removing any dependencies on the model.   The return type of the execute method is ActionForward which is used by the Struts Framework to forward the request to the file as per the value of the returned ActionForward object..

Q8. Write code of any Action Class?

package com.durgasoft;
import javax.servlet.http.*;
import org.apache.struts.action.*;
public class TestAction extends Action
{
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request,HttpServletResponse response) throws Exception
   {
      return mapping.findForward("success");
}
}

Q9. What is ActionForm?

Any java class which extends from org.apache.struts.action.ActionForm is called ActionForm. An ActionForm is also called JavaBean. ActionForm maintains the session state for web application and the ActionForm object is automatically populated on the server side with data entered from a form on the client side.

Q10. What is Struts Validator Framework?

Struts Framework provides the functionality to validate the form data. It can be use to validate the data on the users browser as well as on the server side. Struts Framework emits the java scripts and it can be used validate the form data on the client browser. Server side validation of form can be accomplished by sub classing your From Bean with DynaValidatorForm class.
The Validator framework was developed by David Winterfeldt as third-party add-on to Struts. Now the Validator framework is a part of Jakarta Commons project and it can be used with or without Struts. The Validator framework comes integrated with the Struts Framework and can be used without doing any extra settings.

Q11. How you will display validation fail errors on jsp page?

         Following tag displays all the errors:
              <html:errors/>

Q12. What is RequestProcessor?

The controller is responsible for intercepting and translating user input into actions to be performed by the model. The controller is responsible for selecting the next view based on user input and the outcome of model operations. The Controller receives the request from the browser, invoke a business operation and coordinating the view to return to the client.The controller is implemented by a java servlet, this servlet is centralized point of control for the web application. In struts framework the controller responsibilities are implemented by several different components like
The ActionServlet Class
The RequestProcessor Class
The Action Class
The ActionServlet extends the javax.servlet.http.httpServlet class. The ActionServlet class is not abstract and therefore can be used as a concrete controller by your application.
The controller is implemented by the ActionServlet class. All incoming requests are mapped to the central controller in the deployment descriptor as follows.
      <servlet>
        <servlet-name>action</servlet-name>
        <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
       </servlet>
All request URIs with the pattern *.do are mapped to this servlet in the deployment descriptor as follows.
<servlet-mapping>
       <servlet-name>action</servlet-name>
       <url-pattern>*.do</url-pattern>
<servlet-mapping>
          A request URI that matches this pattern will have the following form.
http://localhost:8080/mycontext/actionName.do
The preceding mapping is called extension mapping, however, you can also specify path mapping where a pattern ends with /* as shown below.
<servlet-mapping>
   <servlet-name>action</servlet-name>
   <url-pattern>/do/*</url-pattern>
   <url-pattern>*.do</url-pattern>
A request URI that matches this pattern will have the following form.
http://localhost:8080/mycontext/do/action_Name The class
org.apache.struts.action.requestProcessor process the request from the controller. You can sublass the RequestProcessor with your own version and modify how the request is processed.
Once the controller receives a client request, it delegates the handling of the request to a helper class. This helper knows how to execute the business operation associated with the requested action. In the Struts framework this helper class is descended of org.apache.struts.action.Action class. It acts as a bridge between a client-side user action and business operation. The Action class decouples the client request from the business model. This decoupling allows for more than one-to-one mapping between the user request and an action. The Action class also can perform other functions such as authorization, logging before invoking business operation. the Struts Action class contains several methods, but most important method is the execute() method.
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response)    throws Exception
      The execute() method is called by the controller when a request is received from a client. The controller creates an instance of the Action class if one doesn?t already exist. The strut framework will create only a single instance of each Action class in your application.
       Action are mapped in the struts configuration file and this configuration is loaded into memory at startup and made available to the framework at runtime. Each Action element is represented in memory by an instance of the org.apache.struts.action. ActionMapping class. The ActionMapping object contains a path attribute that is matched against a portion of the URI of the incoming request.
<action>
        path= "/somerequest"
        type="com.somepackage.someAction"
        scope="request"
        name="someForm"
        validate="true"
        input="somejsp.jsp"
    <forward name="Success" path="/action/xys" redirect="true"/>
    <forward name="Failure" path="/somejsp.jsp" redirect="true"/>
</action>
         Once this is done the controller should determine which view to return to the client. The execute method signature in Action class has a return type org.apache. struts.action.ActionForward class. The ActionForward class represents a destination to which the controller may send control once an action has completed. Instead of specifying an actual JSP page in the code, you can declaratively associate as action forward through out the application. The action forward are specified in the configuration file.
<action>
        path= "/somerequest"
        type="com.somepackage.someAction"
        scope="request"
        name="someForm"
        validate="true"
        input="somejsp.jsp"
    <forward name="Success" path="/action/xys" redirect="true"/>
    <forward name="Failure" path="/somejsp.jsp" redirect="true"/>
</action>
The action forward mappings also can be specified in a global section, independent of any specific action mapping.
<global-forwards>
    <forward name="Success" path="/action/somejsp.jsp" />
    <forward name="Failure" path="/someotherjsp.jsp" />
</global-forwards>

Q13. How you will handle exceptions in Struts?

In Struts you can handle the exceptions in two ways:
   a) Declarative Exception Handling: You can either define global exception handling tags in your struts-config.xml or define the exception handling tags within
<action>..</action> tag.

Example:
<exception
    key="database.error.duplicate"
      path="/UserExists.jsp"
      type="mybank.account.DuplicateUserException"/>
   b) Programmatic Exception Handling: Here you can use try{}catch{} block to handle the exception.

Q14. What are the different kinds of actions in Struts?

The different kinds of actions in Struts are:
ForwardAction, IncludeAction, DispatchAction, LookupDispatchAction, SwitchAction

Q15. What is DispatchAction?

The DispatchAction class is used to group related actions into one class. Using this class, you can have a method for each logical action compared than a single execute method. The DispatchAction dispatches to one of the logical actions represented by the methods. It picks a method to invoke based on an incoming request parameter. The value of the incoming parameter is the name of the method that the DispatchAction will invoke.

Q16. How to use DispatchAction?

To use the DispatchAction, follow these steps :

Create a class that extends DispatchAction (instead of Action)
In a new class, add a method for every function you need to perform on the service – The method has the same signature as the execute() method of an Action class.
Do not override execute() method – Because DispatchAction class itself provides execute() method.
Add an entry to struts-config.xml

Q17. What is LookupDispatchAction?

The LookupDispatchAction is a subclass of DispatchAction. It does a reverse lookup on the resource bundle to get the key and then gets the method whose name is associated with the key into the Resource Bundle.

Q18. What is the use of LookupDispatchAction?

LookupDispatchAction is useful if the method name in the Action is not driven by its name in the front end, but by the Locale independent key into the resource bundle. Since the key is always the same, the LookupDispatchAction shields your application from the side effects of I18N.

Q19. What is difference between LookupDispatchAction and DispatchAction?

The difference between LookupDispatchAction and DispatchAction is that the actual method that gets called in LookupDispatchAction is based on a lookup of a key value instead of specifying the method name directly.

Q20. What is SwitchAction?

The SwitchAction class provides a means to switch from a resource in one module to another resource in a different module. SwitchAction is useful only if you have multiple modules in your Struts application. The SwitchAction class can be used as is, without extending.

Q21. What if <action> element has <forward> declaration with same name as global forward?

In this case the global forward is not used. Instead the <action> element’s <forward> takes precendence.

Q22. What is difference between ActionForm and DynaActionForm?

An ActionForm represents an HTML form that the user interacts with over one or more pages. You will provide properties to hold the state of the form with getters and setters to access them. Whereas, using DynaActionForm there is no need of providing properties to hold the state. Instead these properties and their type are declared in the struts-config.xml.
The DynaActionForm bloats up the Struts config file with the xml based definition. This gets annoying as the Struts Config file grow larger.
The DynaActionForm is not strongly typed as the ActionForm. This means there is no compile time checking for the form fields. Detecting them at runtime is painful and makes you go through redeployment.
ActionForm can be cleanly organized in packages as against the flat organization in the Struts Config file.
ActionForm were designed to act as a Firewall between HTTP and the Action classes, i.e. isolate and encapsulate the HTTP request parameters from direct use in Actions. With DynaActionForm, the property access is no different than using request.get Parameter( .. ).

DynaActionForm construction at runtime requires a lot of Java Reflection (Introspection) machinery that can be avoided.

Q23. What is the life cycle of ActionForm?

The lifecycle of ActionForm invoked by the RequestProcessor is as follows:

Retrieve or Create Form Bean associated with Action
"Store" FormBean in appropriate scope (request or session)
Reset the properties of the FormBean
Populate the properties of the FormBean
Validate the properties of the FormBean
Pass FormBean to Action

Q24.What are the important tags of struts-config.xml ?

<struts-config>

<form-beans>
<form-bean name="login" type=" LoginForm" />

</form-beans>

<global-forwards>

</global-forwards>

<action-mappings>

<action

path="/login"

type="LoginAction" >

</action>

</action-mappings>

<message-resources parameter="MessageResources" />

<plug-in className="org.apache.struts.validator.ValidatorPlugIn">

<set-property

property="pathnames"

value="/org/apache/struts/validator/validator-rules.xml,

/WEB-INF/validation.xml"/>

</plug-in>

</struts-config>

Q25. What are the core classes of the Struts Framework?

A: Core classes of Struts Framework are ActionForm, Action, ActionMapping, Action Forward, ActionServlet etc.

Q26. What is action mappings?
An action mapping is a configuration file entry that, in general, associates an action name with an action. An action mapping can contain a reference to a form bean that the action can use, and can additionally define a list of local forwards that is visible only to this action.

Q27. Describe validate() and reset() methods ?

validate () and reset() methods defined inActionForm class.
validate() : Used to validate properties after they have been populated; Called before FormBean is handed to Action. Returns a collection of ActionMessage as ActionErrors. Following is the method signature for the validate() method.
public ActionErrors validate(ActionMapping mapping, HttpServletRequest request)
reset(): reset() method is called by Struts Framework with each request that uses the defined ActionForm. The purpose of this method is to reset all of the ActionForm's data members prior to the new request values being set.
public void reset() {}

Q28. Give the Details of XML files used in Validator Framework?
The Validator Framework uses two XML configuration files validator-rules.xml and validation.xml. The validator-rules.xml defines the standard validation routines, these are reusable and used in validation.xml. to define the form specific validations. The validation.xml defines the validations applied to a form bean.

Q29. How you will enable front-end validation based on the xml in validation.xml?
The <html:javascript> tag to allow front-end validation based on the xml in validation.xml. For example the code: <html:javascript formName="logonForm" dynamicJavascript="true" staticJavascript="true" /> generates the client side java script for the form "logonForm" as defined in the validation.xml file. The <html:javascript> when added in the jsp file generates the client site validation script.

Q30. What is the difference between perform() and execute() methods?
perform() method defined in Struts 1.0. but it is was deprecated in the Struts Version 1.1. In Struts 1.x, Action.perform() is the method called by the ActionServlet. This is typically where your business logic resides, or at least the flow control to your JavaBeans and EJBs that handle your business logic. As we already mentioned, to support declarative exception handling, the method signature changed in perform. Now execute just throws Exception. Action.perform() is now deprecated; however, the Struts v1.1 ActionServlet is smart enough to know whether or not it should call perform or execute in the Action, depending on which one is available.

Q31. What are the various Struts tag libraries?
Struts is very rich framework and it provides very good and user friendly way to develop web application forms. Struts provide many tag libraries to ease the development of web applications. These tag libraries are:
* Bean tag library - Tags for accessing JavaBeans and their properties.
* HTML tag library - Tags to output standard HTML, including forms, text boxes, checkboxes, radio buttons etc..
* Logic tag library - Tags for generating conditional output, iteration capabilities and flow management
* Tiles or Template tag library - For the application using tiles
* Nested tag library - For using the nested beans in the application

Q32. What are the difference between <bean:message> and <bean:write>?
<bean:message>: This tag is used to output locale-specific text (from the properties files) from a MessageResources bundle.
<bean:write>: This tag is used to output property values from a bean. <bean:write> is a commonly used tag which enables the programmers to easily present the data.

Q33. What are difference between ActionErrors and ActionMessage?
ActionMessage: A class that encapsulates messages. Messages can be either global or they are specific to a particular bean property.
Each individual message is described by an ActionMessage object, which contains a message key (to be looked up in an appropriate message resources database), and up to four placeholder arguments used for parametric substitution in the resulting message.
ActionErrors: A class that encapsulates the error messages being reported by the validate() method of an ActionForm. Validation errors are either global to the entire ActionForm bean they are associated with, or they are specific to a particular bean property (and, therefore, a particular input field on the corresponding form).

Q34. What is the use of ForwardAction?
The ForwardAction class is useful when you’re trying to integrate Struts into an existing application that uses Servlets to perform business logic functions. You can use this class to take advantage of the Struts controller and its functionality, without having to rewrite the existing Servlets. Use ForwardAction to forward a request to another resource in your application, such as a Servlet that already does business logic processing or even another JSP page. By using this predefined action, you don’t have to write your own Action class. You just have to set up the struts-config file properly to use ForwardAction.

Q35. What is IncludeAction?
The IncludeAction class is useful when you want to integrate Struts into an application that uses Servlets. Use the IncludeAction class to include another resource in the response to the request being processed.

Q36. What are the steps need to use DynaActionForm?
Using a DynaActionForm instead of a custom subclass of ActionForm is relatively straightforward. You need to make changes in two places:
In struts-config.xml: change your <form-bean> to be an org.apache.struts.action.Dyna ActionForm instead of some subclass of ActionForm

<form-bean name="loginForm"
           type="org.apache.struts.action.DynaActionForm" >
    <form-property name="userName" type="java.lang.String"/>
    <form-property name="password" type="java.lang.String" />
</form-bean>
In your Action subclass that uses your form bean:

import org.apache.struts.action.DynaActionForm
downcast the ActionForm parameter in execute() to a DynaActionForm
access the form fields with get(field) rather than getField()

Q37. In struts what happens if made any changes in actionservlet?

The ActionServlet plays the role of controller wich is responsible for handling the request and selecting the correct Application Module and storing ApplicationConfig and MessageResource bundle in the request object.
If we modify the ActionServlet the Controller may or may not work what happens that depends on your modification, You have not specify whether you want to create your own custom ActionServlet by extending ActionServlet and overriding the methods in it or what exactly you want to modify.

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Java Hibernate Tutorial With Eclipse Installation and How to use Eclipse

2011-03-01T20:12:00.000+05:30

Hibernate Tutorials With Eclipse IDE Part 1

Hibernate Tutorials With Eclipse IDE Part 2

Hibernate Tutorials With Eclipse IDE Part 3

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2011-02-25T00:55:00.000+05:30

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Java FAQ'S and Java Interview Tips, Java Videos,Tutorials,classes, HTML,JavaScript,Log4J Steps. Struts FAQ, Spring FAQ, Hibernate FAQ MyEclipse & NetBeans IDE Shortcuts...etc

2011-02-11T01:00:00.001+05:30

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How to Install Oracle 9i or Oracle 10g Installation Help

2011-02-10T15:52:00.000+05:30

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Oracle 9i or 10g Installation Help

1. Download Oracle 9i or 10g Software.

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6. Select Enterprise Edition

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9. Write SID (Source ID) Names

Global Database Name : Harisid

SID : Harisid

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20. Enter your Own Password : tiger

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How to Install MySQL on a Windows Server

Install MySQL on a Windows Server

To install MySQL, please follow these steps:

JQuery Auto Complete Box

Java History

Father of Java James Gosling Complete History

James Gosling Is The Father of the Java:

Educational Qualifications of James Gosling:

Refer FAQ Questions and Improve Your Java Skills

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Improve Your Java Skills

C-Language Aptitude Questions & Answers

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What is Unit Testing..?

What is Unit Testing

Unit Testing...?

How to Install Oracle 9i or 10g Software Installation Picture Help

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Hibernate FAQ'S

Spring FAQ'S

Struts FAQ'S

Java Hibernate Tutorial With Eclipse Installation and How to use Eclipse

Hibernate Tutorials With Eclipse IDE Part 2

Hibernate Tutorials With Eclipse IDE Part 3

Java2Hari Videos

An Interview with James Gosling "Why It Named Java".

James Gosling Interview at JavaOne 2009 (Part 1 of 3)

Student Q&A with James Gosling

First Java Hello World Program Using Standalone & Eclipse IDE Videos

Java FAQ'S and Java Interview Tips, Java Videos,Tutorials,classes, HTML,JavaScript,Log4J Steps. Struts FAQ, Spring FAQ, Hibernate FAQ MyEclipse & NetBeans IDE Shortcuts...etc

How to Install Oracle 9i or Oracle 10g Installation Help

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