JavaTutorial Blog,Android tutorial

Android Studio Temperature Conversion

2015-04-15T11:27:00.001-07:00

Hi , Now I am moving towards new Program that is Android Studio Calculator , a very basic calculator which will look as below :

Temperature Converter Android Studio

This link has been moved to a new site here -----> Android Studio Temperature Conversion
http://www.javainhouse.com/2016/01/android-studio-temperature-conversion.html

WAP to find first Position of a String in another String

2015-02-13T12:31:00.001-08:00

Hi , My today's post is on a program to find Position of a String in another String.
For Example ,Given two strings, A and B, how to find the first position of B in A? For instance, A = " ab123cdefgcde"; B= "cde" Then the first position of B in A is 6.

import java.util.Scanner;

public class SB

{

public static void main(String[] args) {

{
String test=null;
String index=null;
int j=0;
System.out.println("Enter the string");
test= new Scanner(System.in).nextLine();
System.out.println("Enter the substring you want to count");
index= new Scanner(System.in).nextLine();
for (int i = 0; i <= test.length()-index.length(); i++) {
String testing=test.substring(i, index.length()+i);

if(testing.equals(index))
{
j=i+1;
System.out.println("It occurs first at "+ j +" position" );
break;
}
}

}
}
}

Android Studio Calculator Example

2015-02-07T05:29:00.000-08:00

Hi , Now I am moving towards new Program that is Android Studio Calculator , a very basic calculator which will look as below :

This link has been moved to new address

http://www.javainhouse.com/2016/01/android-studio-calculator-example.html

Android Button Example

2015-02-05T09:29:00.001-08:00

Hi Today's my post on How to use Button in Android .Button is a UI widget . If you are very beginner first go through my first example of Android Hello World which helps you how to run a very basic program in android.

This link has been moved to new address : http://www.javainhouse.com/2016/01/button-example-android-studio.html

Hello World Android Studio

2015-02-01T10:33:00.000-08:00

Hi, After installing Android Studio Let us see how to create our very first program Hello World

This link has been moved to a new site here -----> Hello World Android Studio

Step 8: Run

Run this program and this will show you the output on emulator .I am using Nexus 7 as AVD .How to add a AVD in your studio you can see here.

Hello World Android

If you are facing some errors in running the above program you can refer below as I was also facing many errors so I have drafted them for your help .

See :

Android Button Example

Calculator with Android Studio

Android Studio Installation

2015-02-01T10:14:00.001-08:00

Android Studio is the official IDE for Android application development, based on IntelliJ IDEA. On top of the capabilities you expect from IntelliJ, Android Studio offers:

Flexible Gradle-based build system
Build variants and multiple apk file generation
Code templates to help you build common app features
Rich layout editor with support for drag and drop theme editing
Lint tools to catch performance, usability, version compatibility, and other problems
ProGuard and app-signing capabilities
Built-in support for Google Cloud Platform, making it easy to integrate Google Cloud Messaging and App Engine

You can download Android Studio from the link below:

http://developer.android.com/sdk/index.html

After downloading Android Studio keep on clicking next and install android studio .

You may like :
Android Studio Hello World Program

Android Button Example

Program for Shifting characters in a String eg. String "abcde" should be printed as "eabcd"

2015-01-27T21:40:00.000-08:00

import java.util.Scanner;

public class SB
{
public static void main(String []args) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a string to shift characters");
String test = in.nextLine();

For further visit Javainhouse

Find length of String without using any length or size method

2015-01-24T11:09:00.001-08:00

import java.util.Scanner;

public class SB

{

public static void main(String[] args) {

{
String test;
Scanner in = new Scanner(System.in);

For further program please visit my new blog http://javainhouse.blogspot.com

Print "welcome bangalore" as welcome erolagnab

2015-01-24T10:24:00.000-08:00

import java.util.Scanner;

public class SB

{

public static void main(String[] args) {

{
String test="welcome bangalore";

String reverse="";

int i=0;

String a[]=test.split(" ");

for (int j = a[1].length()-1; j >= 0; j--)
{

reverse = reverse + a[1].charAt(j);
}

a[1]=reverse;
test=a[0] +" "+ a[1];
System.out.println(test);

}
}
}

Program in java to check whether a String is palindrome or not

2015-01-22T10:54:00.000-08:00

import java.util.*;

public class Palindrome

{

public static void main(String args[])

{

String original, reverse = "";

Scanner in = new Scanner(System.in);

Program in java to check whether a String is palindrome or not System.out.println("Enter a string to check palindrome");

original = in.nextLine();

int length = original.length();

for ( int i = length - 1 ; i >= 0 ; i-- )

reverse = reverse + original.charAt(i);

if(reverse.equals(original))

System.out.println("Yes String is palindrome");

else

System.out.println("NO String is not palindrome");

}

Program to split a String without using split() method

2015-01-22T10:48:00.000-08:00

Program to split a String without using split() method import java.util.*;
public class SplitString
{
public static void main(String[] args) {
String[] s = {"Netherlands_Iceland_Norway_Denmark"};
String[] finalString = mymethod(s);
for (int i = 0; i < s.length; i++) {
System.out.println("" + finalString[i]);
}
}

static public String[] mymethod(String[] mystring) {
String ss[] = new String[mystring.length];
for (int j = 0; j < mystring.length; j++) {
ss[j] = mystring[j].replace('_', ' ');
}
return ss;
}
}

Introduction to JAXB and its Architecture

2015-01-19T08:58:00.000-08:00

JAXB means JAVA API for XML Binding.

Introduction to JAXB and its Architecture In simple words, it means an API used to bind XML with JAVA objects.

JAXB provides an efficient and easy way to bind XML data to JAVA which is very helpful for java developer ,Mostly used in case of web services as data travel between web services and client in form of xml which is further needed to be converted into java object as a need for java application.This need can be fulfilled by JAXB.

Mainly two things can be understood as working of JAXB.
1. Conversion of java objects to XML which is known as Marshalling.
2. Conversion of XML data to java object ,known as unmarshalling.

JAXB Architecture:

JAXB Architecture

JAXB Architecture consists of following components:

Schema Compiler
Schema Generator
Binding Runtime Framework

Schema Compiler is used to bind source schema with schema derived program elements.

Schema Generator maps set of Program elements to derived schema .This mapping is described by annotations.

Binding Runtime Environment : Provides unmarshalling (reading) and marshalling (writing) operations for accessing, manipulating, and validating XML content using either schema-derived or existing program elements.

How Hashmap works internally in java

2014-12-20T10:22:00.000-08:00

This page has been moved to our new blog http://www.javainhouse.com/2016/05/hashmap-internal-working-java.html

Difference between equals() and ==

2014-12-10T04:27:00.001-08:00

Difference between equals() and ==

Hi all , these days i\'m about to write a post on very fashionable interview question that is what\'s the difference between equals and == .It is asked in every object familiarised language interview whether or not its Java or ASP.NET For this you must apprehend the essential difference between each .

1. The very first difference in both is that equals () is a method == is an operator . this can be the terribly basic factor you must understand equals and ==
As in java there\'s no concept of operator overloading thus we cannot modify the behavior of == operator.

2. “= = “operator : “= =” is a binary operator used to compare both primitive sorts like int ,Boolean and objects .
While examination primitive sort its works properly and returns right output
For example :

int a=1;
int b=2;

if(a==b)

else

Output : Not Equal;

While examination 2 objects using “==” ,a problem arises is that “= =” checks reference of each objects not price and returns output correspondingly .

This can be illustrated with the assistance of associate example :

String variable1=new String(“First”);
String variable2=new String(“First);

If(variable1==variable2)

else

Output: Not Equal

In the example above as variable1 and variable2 ar referring to 2 totally different objects despite of same price .Accordingly “==” operator can come false compared each

String variable1=new String(“First”);
String variable2=variable1;

If(variable1==variable2)

else

Output: Equal

In the example above as variable1 and variable2 ar referring to 2 same objects .Accordingly “==” operator can come true compared each

3. equals () : equals() method is used to compares the worth of 2 objects . this method is defined in Object class and can even be overridden to change the working

String variable1=new String(“First”);
String variable2=variable1;

If(variable1.equals(variable2))

else

Output: Equal

In the example above as variable1 and variable2 are referring to 2 totally different objects with same price .Accordingly equals() will come true compared each.

you may like :

How objects are stored in heap ?

How to create custom Exception in Java

2014-12-07T07:57:00.003-08:00

How to create custom Exception in Java

Custom Exception

Why we need custom Exception ?
How to create a custom exception ?
Write code to create a Custom Exception

All these are questions usually asked in a Java interview .So my today's post on how to create a custom exception in java .

As we know There are two types of Exception :
1. Checked Exception
2. Unchecked Exception

Both these exceptions have a common parent class Exception .So ,in same order if we have to create a custom exception ,we need to extend Exception class.

Ok , let me explain the process step by step .

1. Any custom exception should extend Exception Class .

2. There should be a proper name given to the Exception ,For example if there is an exception related to Invalid age name can be given as InvalidAgeException

public class InvalidAgeException extends Exception {}

public class InvalidAgeException extends Exception {
private int age;

public InvalidAgeException ()
{
super();
}
public InvalidAgeException (String message, int age)

{
super(message);

this.age = age;

}

}

In the above way we can define two constructors of InvalidAgeException with message and without message

Usage of custom Exception:

Below is the program with usage of custom exception.

public class CustomExceptionDemo

{

private static final Map<Integer, String> employee = new HashMap<>();

static

{
employee.put(100, "Mahesh");

employee.put(101, "Suresh");

employee.put(102, "Bran");

employee.put(103, "Troy"); }

public static void main(String args[]) {

CustomExceptionDemo t = new CustomExceptionDemo();

t.getAge(1000); }

public String getAge(int age)

{

if (employee.get(age) == null)

{

throw new InvalidAgeException ("No such employee exists", age);

} return employee.get(name);

}

}

SO friends this was my post on Custom Exception .

What is design pattern in java?

2014-11-30T22:14:00.001-08:00

design pattern in java

Design Pattern :

Design pattern are answer to common occurring problem in software system development . Design pattern are language independent solution that are developed to solve common object oriented issues .
They if used sensibly helps to extend code maintainability , reduces learning curve whereas developing a bit of code ,makes development quicker ,reduces TCO (total value output) and helps to simply understand solution to new developer.

Singleton Design Pattern :
Singleton Design pattern uses a singleton class which should have a single instance.
Singleton design pattern ensures that at a single point of time only a single instance should be present in JVM Singleton class should also provide a method which acts as a single point for global access of that class.

Common approach for a singleton pattern :
1. Singleton class should have a private constructor so that no other class can instantiate it .
2. Singleton class should have a private static variable of the class that will be the only instance of that class.
3. A public static method which is the only global access point for outer world.

You may like :
Difference between equals() and = =

Count the Number of Vowels in Java String

2014-11-30T11:06:00.000-08:00

import java.util.Scanner;

public class SB

{

public static void main(String[] args) {

{
String test=null;

int j=0;

char index[]={'a','e','i','o','u'};

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

test= new Scanner(System.in).nextLine();

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

for (int k = 0; k < index.length; k++)
{
char element=test.charAt(i);

if(element == index[k])
{
j++;

}
}
}
System.out.println("No of vowels are "+j);
}
}
}

find the substring count from a string without string functions in java

2014-11-30T09:40:00.000-08:00

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;

public class SB

{

public static void main(String[] args) {

{
String test=null;
String index=null;
int j=0;
System.out.println("Enter the string");
test= new Scanner(System.in).nextLine();
System.out.println("Enter the substring you want to count");
index= new Scanner(System.in).nextLine();
for (int i = 0; i <= test.length()-index.length(); i++) {
String testing=test.substring(i, index.length()+i);

if(testing.equals(index))
{
j++;

}
}
System.out.println("No of count is "+j);
}
}
}

Program to remove a particular character from a sentence

2014-11-30T00:57:00.000-08:00

public class SB

{
public static void main(String[] args) {

{
String test=null;
char remove = 0;
System.out.println("Enter the String");
test = new Scanner(System.in).nextLine();
System.out.println("Enter the Character to be removed");
remove=new Scanner(System.in).nextLine().charAt(0);
StringBuilder newstring =new StringBuilder();
for (int i = 0; i < test.length(); i++) {
if(remove==test.charAt(i))
{
continue;
}
newstring.append(test.charAt(i));
}
System.out.println(newstring);
}

}

}

You may like :
Difference between equals() and = =
Singleton Design Pattern
Other Programs in Java
Custom Exception in Java -Tutorial

Program to find a prime number in java

2014-11-29T01:06:00.000-08:00

import java.util.Scanner;

public class SB

{

public static void main(String[] args) {
System.out.println("Enter the limit uptoo which you want to print prime no.");
int in = new Scanner(System.in).nextInt();
int limit =in;
for (int i = 2; i <=limit; i++) {

For further visit Javainhouse

You may like :

Design Pattern in java

Java Coding Interview Questions

Count no.of times a word repeats in String in Java

2014-11-27T11:55:00.000-08:00

public class SB

{

public static void main(String[] args) {
String test="Hi I am here am am too good am very a m";
String find="am";
int i=0;

String a[]=test.split(" ");
for (int j = 0; j < a.length; j++) {
if(a[j].equals(find))
{
i++;
}
}

System.out.println(i);

}

}

Program in java to find a String in a sentence

2014-11-27T11:42:00.000-08:00

Hi all
I am writing a program to find whether a particular word exists in a sentence or not .

public class SB

{

public static void main(String[] args) {
String test="Hi I am here";
String find="am";

if(test.indexOf(find)>0)
{
System.out.println("found ");
}
else
{
System.out.println("not found");
}
}

}

output: found

------------------------------------------------------------------------------------

public class SB

{

public static void main(String[] args) {
String test="Hi I am here";
String find="kill";

if(test.indexOf(find)>0)
{
System.out.println("found am");
}
else
{
System.out.println("not found");
}
}

}

output : not found

Top Java Collections interview Questions

2014-11-25T01:27:00.001-08:00

1.What is Java Collection Framework?

Ans : Java Collections Framework is also known as JCF. It is a set of classes and Interfaces that implement commonly used data structures like List ,Linked List etc.

2. Explain Collection Framework in detail or what all collections are present in Java Collection Framework ?
Ans : Java Collection Framework architecture consists of many collections Like List,Set ,Map etc . You can find detailed description of this framework here.

3. Why Map interface does not extends Collection interface ?
Ans : Map is a part of Collections framework but does not extend Collections Interface as its behaviour is different from normal Collections like List and set :
The reason that can be tell in an interview that :
a) Map contains key value pair to store data in it while other collections like list and set directly stores elements in them .
b) add() method is not used in map to add an element.

4. What is List interface? What are all its implementations?
Ans : List is an ordered collection of elements .The ordering is index based .List can conatin duplicate elements. The implementation of lIst are :
a) ArrayList
b) Vector
c) Linkedist
d) Stack

5. What is an arrayList?
Ans :ArrayList is an implementation of List which is backed by an array .ArrayList is re-sizable array implementation of List interface and implements all operations of List interface,permits all elements including null .

eg.
List<String> l= new ArrayList<String>();

or

ArrayList<String> l= new ArrayList<String>();

6.Internal Working of an ArrayList

Ans : Internal working of an ArrayList is very important question with interview perspective .Interviewer asks this question to know how deeply the candidate know about this structure .As you know ArrayList is backed by an array only ,but how this array is defined and how elements are added into this array you can read it in detail here .:

Internal Working of an ArrayList

7. Difference between Array and arrayList.

Array	ArrayList
Arrays are fixed in size and cannot be resized dynamically	ArrayList is dynamic and resizablei in nature
Once the array is created elements cannot be added or deleted from it	ArrayList the elements can be added and deleted at runtime.
Can be multidimensional	Can’t be multidimensional
Array can contain objects of a single data type or class	ArrayList if not used with generic can contain objects of different classes
Example : Int [] arr={1,2};	Example : List lis= new ArrayList(); lis.add(1); lis.add(“John”);

8 .How to sort an array list ?
Ans : To sorting an array list we can use various techniques .

1. Without using any sort method .
2. Using sort method
3. Using Comparator and Comparable

1. To sort an array List without using sort method ,we need to use a sorting algorithm .which can be bubble sort

2. using sort method

To sort an array List using sort method we will use collections.sort

eg. We have an array List
List l= new ArrayList();
l.add(123);
l.add(80);
l.add(67);
l.add(12);
collections.sort(l);
for (int i :l)
system.out.println(l);

Output : 12
67
80
123

3. Using Comparator and Comparable
If you want to sort an arrayList<Object > then we need to use comparable and comparator interface .
This is very important question to sort collection using comparable and comparator interface .You can find detailed description here .

9. What is the order of the elements are stored in an array List ?
Ans : The order of the elements stored in arrayList is same they are added to the List .
For arrayList ,LinkedList,Vector order of the elements stored in arrayList is same they are added to the List .

10.What is difference between Arrays.sort() and collections.sort() ?
Ans : The main difference between arrays.sort() and collections.sort() is that the former is used to sort arrays and latter is used to sort collections like list .You can further read detailed description on difference between Arrays.sort() and collections.sort() here :

Difference between Arrays.sort() and collections.sort()

11. What is Linked List in Java Collections ?
Ans : Linked List is doubly linked list implementation of list interface .Please don't confuse linked list in collection with linked list in data structure as that one in data structure can be both singly link list or doubly .
Linked List implements all of the methods of list interface and permits all kind elements including null.

Java Interview Questions

2014-11-24T03:37:00.001-08:00

Q1. How can you get to know that whether one object belongs to a particular class ?

Ans : using instanceof

The instanceof operator tests whether an object has in its prototype chain theprototype property of a constructor.

Eg :

We have a class test with a object

Test t1= new Test();

And another class Testing t2 = new Test();

If we have to find that whether t2 belong to Test class or not we will use

System.out.println(t2 instanceof Testing); //print true

      System.out.println(t2 instanceof Test); //printfalse

Java Collections Interview Questions

Life cycle of a thread in java

2014-11-23T04:21:00.001-08:00

Life cycle of a thread in java

Life cycle of a thread contains following stages :

New

Runnable

Running

Blocked or Non running

Terminated

Release 5.0 introduced the Thread.getState method. When called on a thread, one of the following Thread.State values is returned:

NEW
RUNNABLE
BLOCKED
WAITING
TIMED_WAITING
TERMINATED

New : State of Thread before start() method .

Runnable : A thread is in running state after invocation of start() method but has not yet selected by scheduler .

Running : After Scheduler select the thread to run and run() method starts executing then that thread it comes in running state.

Blocked or NonRunning : when a thread goes into wait() or sleep state then its called to be in non running or blocked .It comes into runnable state only if notify or notifyAll() is called on that thread.

Terminated : after a thread is being stopped by stop () method ,it comes into terminated state and can never go back to runnable or running state .