Java Technology PROGRAMS in APPLETS, SWING, JAVA SERVLETS, JSP

Custom Exception example for BankAccount

2014-11-23T13:55:00.000+05:30

class BankAccount {
int accountNumber;

double accountBalance;

public BankAccount(int accountNumber, double accountBalance) {
this.accountNumber = accountNumber;
this.accountBalance = accountBalance;
}

public int getAccountNumber() {
return accountNumber;
}

public double getAccountBalance() {
return accountBalance;
}

public boolean withdraw (double amount) throws WithdrawLimitException
{
if( amount > accountBalance)
{
throw new WithdrawLimitException("Withdrawing Amount is more than Balance amount.. ");

// return false;
}

else
{
accountBalance -= amount;

return true;
}

}

public boolean deposit(double amount)
{
if( amount < 0.0)
{
return false; // can not deposit a negative amount
}

else
{
accountBalance += amount;
return true;
}

}
}

class WithdrawLimitException extends Exception {

public WithdrawLimitException(String message) {
super(message);
}

}

// Application Class

public class BankAccountMainExample {

public static void main(String[] args) {

BankAccount ba = new BankAccount(101,10000);

if (!(ba.deposit(20000))) {
System.out.println("Negative amount can not be deposited..");
}

try {
ba.withdraw(70000);
} catch (Exception e) {
System.out.println(e);
}

System.out.println("Account balance : "+ ba.getAccountBalance());

}
}

Application class for Generic Stack Implementation

2014-11-23T13:50:00.002+05:30

class MyThread extends Thread {

MyGenericStack<Integer> iobj;
String thname;

public MyThread(MyGenericStack<Integer> iobj, String n) {
this.iobj = iobj;
thname=n;
}

public void run() {
int no=1001;
for (int i=0;i<40;i++)
{
if (thname.equals("1")) {

if (iobj.push(new Integer(no))==true) {
System.out.println("Thread : "+ thname + " has pushed... " + (no++) );
}
}
else if (thname.equals("2")) {
Object myin = iobj.pop();
System.out.println("Thread : "+ thname + " has poped... "+ myin);

}

}

// iobj.show(); // show method of MyGenericStack class
}
}
public class MyThreadStackExample {
public static void main(String[] args) {

// The object of MyGenericStack can hold elements of any type e.g. String,Double,Student, etc...

MyGenericStack<Integer> mys = new MyGenericStack<Integer>(20);

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

MyThread pt = new MyThread(mys,"1");

MyThread pt2 = new MyThread(mys,"2");

pt.start();
pt2.start();

try {
pt.join();
pt2.join();

} catch (Exception e) {
}

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

}
}

Generic Stack Class with Synchronized methods

2014-11-23T13:49:00.001+05:30

import java.util.ArrayList;

public class MyGenericStack<E> {
E obj;
int capacity;
ArrayList<E> list;

public MyGenericStack(int c) {
capacity=c;
list= new ArrayList<E>(capacity);

}

public synchronized boolean push(E o){

try { Thread.sleep(1000); } catch (Exception e) { System.out.println(e);
}

if (list.size()<20) {
list.add(o);
notifyAll();
return true;
}

return false;
}

public synchronized E pop() {

try { Thread.sleep(1000); } catch (Exception e) { System.out.println(e); }

if (isEmpty()) {
try {
System.out.println("Stack is empty.. Please wait..!");
wait();
} catch (Exception e) {
System.out.println(e);
}
}

obj= list.remove(list.size()-1);
return obj;

}

// If required then uncomment this method
/* public synchronized void show() {
System.out.println("size of stack is : "+ list.size());
if (list.size()>0) {
for (E o : list)
{
System.out.println(o);
}
}
else {
System.out.println("No elements in stack...");
}

}
*/

public boolean isEmpty() { return list.isEmpty(); }
public boolean isFull() { return list.size()>20 ;}

}

enum example 2

2014-11-12T16:03:00.002+05:30

public class testdays {

public enum DaysofWeek {SUN,MON,TUE,WED,THU,FRI,SAT};

public static void main(String[] args) {

DaysofWeek dw= DaysofWeek.MON;

System.out.println("Days of Week : "+ DaysofWeek.valueOf("MON") );

System.out.println(dw);

DaysofWeek[] dws = DaysofWeek.values();

for(DaysofWeek dd:dws)
{
System.out.println(dd);
}

}
}

Static Import

2014-11-12T16:00:00.002+05:30

import static java.lang.Math.*;
import java.util.Date;
import static java.lang.System.*;

public class StaticImportdemo {

public static void main(String[] args) {

out.println(new Date());
out.println(sqrt(25));
out.println(PI);
out.println(abs(-245.56));
out.println(random());

out.println(pow(2, 8));

}
}

JFrame with writing in File using FileWriter and anonymous class example

2014-11-12T15:59:00.000+05:30

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.FileWriter;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class FrameDemo extends JFrame {
JButton btstore;
JTextField jtf, jtf2;
FileWriter fw ;
FrameDemo()
{
jtf = new JTextField(20);
jtf2 = new JTextField(10);
btstore = new JButton("Store");
setLayout(new FlowLayout());

add(jtf); add(jtf2);
add(btstore);

btstore.addActionListener(
new ActionListener() {

public void actionPerformed(ActionEvent ae)
{
String name = jtf.getText();
name = name + " : " + jtf2.getText();
try {
fw = new FileWriter("c:/student.dat", true);
fw.write(name+"\r");
fw.close();

} catch (Exception e) {
System.out.println(e);
}

}
}

);
/* this.addWindowListener(
new WindowAdapter()
{

public void windowClosing(WindowEvent we) {
System.out.println("from window...");
System.exit(0);
}

}
);
*/
add(btstore);

setSize(400,400);
setVisible(true);
setExtendedState(JFrame.MAXIMIZED_BOTH);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

public static void main(String[] args) {
new FrameDemo();
}

}

enum type having private constructor

2014-11-12T15:54:00.000+05:30

public enum SeasonTest
{
WINTER(2), SUMMER(3), FALL(4), SPRING(1);

private int st;

SeasonTest(int t) { st=t; }

public int getSeason() { return st; }

public static void main(String[] args) {

for (SeasonTest ss : SeasonTest.values()) {
System.out.println(ss + " : " + ss.getSeason());
}
SeasonTest s = SeasonTest.SPRING;
System.out.println(s.getSeason());

SeasonTest s1 = SeasonTest.SPRING;
switch(s1) {
case SPRING : System.out.println("Spring"); break;
case SUMMER : System.out.println("Summer"); break;
default : System.out.println("no season.."); break;
}
}
}

Annotation

2014-11-07T16:53:00.000+05:30

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.Date;

/**
*
* @author bhavesh
*/

@Retention(RetentionPolicy.CLASS)
@Target(ElementType.TYPE)
public @interface NewAnnotation {

public String name();
public int myno() default 10;
//public Date mydate =new Date();

}

/**
*
* @author bhavesh
*/

class A
{
public void test()
{

}
}

class B extends A
{
@Override
public void test()
{

}
}

// Use of annotation called NewAnnotation ....

@NewAnnotation(name="ISTAR")
public class ClassAnnotationTest {

}

Enumeration enum

2014-11-07T16:50:00.002+05:30

/**
*
* @author bhavesh
* Season.java
*/
public enum Season {

WINTER(2),MONSOON(3), SUMMER(4);

private int count;

private Season(int count)
{
this.count=count;
}

public int getMaxDays()
{
return count;
}

}

/**
*
* @author bhavesh MainEnumTest.java
*/

public class MainEnumTest {

public static void main(String[] args) {

Season s1 = Season.MONSOON;

s1= Season.SUMMER;
s1 = Season.valueOf("WINTER");

System.out.println("days :"+s1.getMaxDays());

System.out.println("origin "+ s1.ordinal());

}
}

Interface with class and interface as member

2014-11-07T16:12:00.001+05:30

/**
*
* @author bhavesh
*/

public interface MyOuterInterface {

// static class

public class myinn {

private int var;

public void setVar(int v) {

var =v;
}
public int getVar() { return var; }
}

// static interface

public interface myint {

}

}

// Use of above interface with its inner class example

/**

* @author bhavesh

public class MainOuterClass {

public static void main(String[] args) {

MyOuterExample me = new MyOuterExample();

me.callMethod();

}

class MyOuterExample implements MyOuterInterface {

myinn my = new myinn();

public void callMethod() {

my.setVar(20);

System.out.println("value of interface : .. " +my.getVar() );

}

Static and Non Static Inner class example

2014-11-07T16:11:00.001+05:30

/**
*
* @author bhavesh
*/

public class OuterClass {

private static int ox;
private int oy;
public class MyInner1
{
private int x;

public void test()
{
System.out.println(new OuterClass.MyInner2().y);

System.out.println(oy);
}
}

public class MyInner2 {
private int y;

}

public static class Nested1 {
private int z;

public void test2() {
//return Nested2.w;
System.out.println(Nested2.w);
System.out.println(ox);

}
}

public static class Nested2 {

static private int w;

}

}

// Application Class

public class MyOuterApplication {

public static void main(String[] args) {

OuterClass o1 = new OuterClass();

OuterClass.MyInner1 i1 = o1.new MyInner1();

OuterClass.Nested2 n1 = new OuterClass.Nested2();

}

}

Anonymous Class example

2014-11-07T15:53:00.001+05:30

interface MyShape {
static double pi = 3.14;
public double area() ;
public void setValue(int v);
}

public class AnonymousExample
{

public static void main(String args[]) {

MyShape s = new MyShape() {
int myv;
public void setValue(int vv) { myv = vv; }
public double area() { return myv * myv ; }
};

s.setValue(20);
System.out.println(s.area());

}

}

HashMap TreeMap

2014-11-07T15:52:00.001+05:30

import java.util.*;
class Student {
private int stid; private String sname;
private double pert;
Student(int id, String s, double p) {
stid= id;
sname = s;
pert =p;
}
public int getStid() { return stid; }
public String getSname() { return sname; }
public double getPert() { return pert; }

}

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

Student s1 = new Student(303,"Mohin",78.90);
Student s2 = new Student(203,"Dipen",88.90);
Student s3 = new Student(1003,"Jay",98.90);

HashMap<Integer,Student> hhmap = new HashMap<Integer,Student>();

hhmap.put(s1.getStid(),s1);
hhmap.put(s2.getStid(),s2);
hhmap.put(s3.getStid(),s3);
Set<Integer> ttset = hhmap.keySet();
Iterator<Integer> itto = ttset.iterator();
while (itto.hasNext() )
{
Integer i= itto.next();
System.out.print( i + " : ");
Student s = hhmap.get(i) ;
System.out.println(s.getSname() + " : " + s.getPert());

}

System.out.println(" Tree Map Example ");
//Hashmap<Integer, String> hmap = new Hashmap<Integer>();
TreeMap<Integer,String> hmap = new TreeMap<Integer,String>();

hmap.put(301,"Mohin");
hmap.put(201,"Dipen");
hmap.put(1001,"Jay");
hmap.put(101,"Kamlesh");
hmap.put(701,"Digant");
hmap.put(501,"Vishal");
hmap.put(404,"Kaushal");
//hmap.putAll(hhmap);

System.out.println("Hash Map elements : ") ;
System.out.println("TotalSize " + hmap.size());

//System.out.println(hmap.get(404));

Set<Integer> tset = hmap.keySet();
Iterator<Integer> ito = tset.iterator();
while (ito.hasNext() )
{
Integer i= ito.next();
System.out.print( i + " : "+ hmap.get(i) + " \n");

}

hmap.remove(1001);
System.out.println("After remove");

Set<Integer> tset1 = hmap.keySet();
Iterator<Integer> ito1 = tset.iterator();
while (ito1.hasNext() )
{
Integer i= ito1.next();
System.out.print( i + " : "+ hmap.get(i) + " \n");

}

Collection<String> stname = hmap.values();

System.out.println(stname.size());

//System.out.println(hmap.size());
// Print elements of Set using Iterator object
// create iterator object on hashmap

}
}

ArrayList HashSet LinkedHashSet TreeSet

2014-11-07T15:50:00.001+05:30

import java.util.*;

public class MyCollectionExample
{
public static void main(String args[])
{
ArrayList<Integer> alist = new ArrayList<Integer>();

alist.add(301); // alist.add(new Integer(301)); autoboxing alist.add(Integer.valueOf(301));
alist.add(3425);
alist.add(123);
alist.add(4560);
alist.add(123);
alist.add(203);
alist.add(new Integer(301));

System.out.println("Array List elements : ") ;
for (int i=0; i<alist.size(); i++)
{
System.out.println(alist.get(i));
}
// Set example

HashSet<Integer> hset = new HashSet<Integer>();

hset.add(301); // autoboxing alist.add(Integer.valueOf(301));
hset.add(3425);
hset.add(123);
hset.add(4560);
hset.add(123);
hset.add(203);
hset.add(new Integer(301));

System.out.println("Set elements : ") ;
//System.out.println(hset.size());
// Print elements of Set using Iterator object
// create iterator object on hashset

Iterator myit = hset.iterator();

while ( myit.hasNext() )
System.out.println(myit.next());

// Example of LinkedHashSet ordered collection of type set
LinkedHashSet<Integer> lhset = new LinkedHashSet<Integer>();

lhset.add(301); // autoboxing
lhset.add(3425);
lhset.add(123);
lhset.add(4560);
lhset.add(123);
lhset.add(203);
lhset.add(new Integer(301));

System.out.println("Linked Hash Set elements : ") ;

Iterator lmyit = lhset.iterator();

while ( lmyit.hasNext() )
System.out.println(lmyit.next());

// Example of Tree Set ordered collection of type set
TreeSet<Integer> tset = new TreeSet<Integer>();

/* TreeSet<Student> tstudent = new TreeSet<Student>();

Student s1 = new Student(104,"Mohin",70);
Student s2 = new Student(102,"Udit",80);

tstudent.add(s1);
tstudent.add(s2);
*/

tset.add(301); // autoboxing
tset.add(3425);
tset.add(123);
tset.add(4560);
tset.add(123);
tset.add(203);
tset.add(new Integer(301));

System.out.println("Tree Set elements : ") ;

Iterator tmyit = tset.iterator();

while ( tmyit.hasNext() )
System.out.println(tmyit.next());

}
}

Applet with Runnable Interface

2014-11-07T15:47:00.003+05:30

import java.applet.Applet;
import java.awt.*;
import java.util.Random;

public class MyApplet extends Applet implements Runnable {
int x=40, y=40;
Color mycolor = new Color(0,255,255);

public void init() {

}
public void start()
{
Thread myt = new Thread(this);
myt.start();

}

public void update(Graphics g) {

g.setColor(mycolor);
g.fillOval(x,y,60,60);
}

public void run() {
Random myrno = new Random();

//for (int i=0; ; i++) {
while (true) {
try {
mycolor = new Color(myrno.nextInt(255),myrno.nextInt(255),myrno.nextInt(255));

x = myrno.nextInt(300);

y = myrno.nextInt(400);

Thread.sleep(1000);
repaint();

}
catch (Exception e)
{

}
}
}
}

Frame with Menus , Dialog , Panels arranged in BorderLayout

2014-09-30T15:21:00.001+05:30

import java.awt.*;
import java.awt.event.*;
/*class WindowDemo extends Window {
WindowDemo(Frame myf)
{ super(myf);
setSize(200,100);
setVisible(true);
setBackground(Color.red);
}
}*/

public class TestFrameWindow extends Frame implements ActionListener {
private Button btclose,btok;
private Panel pes, pws,pnr, psu,pce;
private Font myf;
private List mylist ;
private TextArea ta;
private Dialog dlg;
private MenuBar mb;
private Menu filem, editm, helpm, workspace;
private MenuItem exitmi, openmi, openallmi;
TestFrameWindow() {

mb = new MenuBar();
setMenuBar(mb);

filem = new Menu("File");
editm = new Menu("Edit");
helpm = new Menu("Help");
workspace = new Menu("WorkSpace..");
mb.add(filem);
mb.add(editm); mb.add(helpm);

exitmi = new MenuItem("Exit");
MenuShortcut shrtct = new MenuShortcut(KeyEvent.VK_X,true);
exitmi.setShortcut(shrtct);
exitmi.addActionListener(this);

filem.add(workspace);
filem.add(exitmi);

openmi = new MenuItem("Open ");
openallmi = new MenuItem("Open All");
workspace.add(openmi); workspace.add(openallmi);

//dialog creation
dlg = new Dialog(this);
dlg.setSize(200,100);
dlg.setTitle("DialogExample");
dlg.add(new Button("OK ...."));

pes = new Panel(); pes.setBackground(Color.red);
pnr = new Panel(); pnr.setBackground(Color.cyan);
psu = new Panel(); psu.setBackground(Color.magenta);
pce = new Panel(); pce.setBackground(Color.green);
pws = new Panel(); pws.setBackground(Color.blue);

btclose = new Button("CLOSE");
myf = new Font("SERIF",Font.BOLD + Font.ITALIC,21);
btclose.setFont(myf);
btok = new Button("OK");

btok.setBackground(Color.gray);
btok.setForeground(Color.yellow);
Dimension mydim = new Dimension(60,60);
btok.setPreferredSize(mydim);
btok.addActionListener(this);
btclose.addActionListener(this);

mylist = new List();
mylist.add("c:");
mylist.add("d:");
mylist.add("e:");

ta = new TextArea(100,60);

add(pes, BorderLayout.EAST);
add(pws , BorderLayout.WEST);
add(pnr, BorderLayout.NORTH);
add(pce , BorderLayout.CENTER);
add(psu, BorderLayout.SOUTH);

psu.add(btclose);
pnr.add(btok);

pws.add(mylist);
pce.add(ta);
//new WindowDemo(this);
//new Window(this).setVisible(true);
setTitle("Frame example");
setSize(400,500);
setBackground(Color.lightGray);
setVisible(true);
setExtendedState(Frame.MAXIMIZED_BOTH);

}

public void actionPerformed(ActionEvent ae ) {

if (ae.getSource().equals(btok) )
{
dlg.setVisible(true);
}
else if (ae.getSource().equals(btclose) )
{
dlg.setVisible(false);
}

if(ae.getSource().equals(exitmi))
{
System.exit(0);
}

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

new TestFrameWindow();
}

}

Various MouseEvent example in an Java Applet

2014-09-17T15:36:00.001+05:30

import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.event.*;

public class TestApplet extends Applet implements MouseListener
{
int px, py;
public void init()
{
setBackground(Color.red);

this.addMouseListener(this);
}

public void paint(Graphics g) {

g.setColor(Color.white);
g.drawString("Welcome Applet", px,py);

}

public void mouseExited(MouseEvent me) {

showStatus("Mouse Exited");
}

public void mouseEntered(MouseEvent me) {
showStatus("Mouse Entered");
}

public void mousePressed(MouseEvent me) {
showStatus("Mouse Pressed");

}

public void mouseReleased(MouseEvent me) {

showStatus("Mouse Released");

}

public void mouseClicked(MouseEvent me) {

px = me.getX();
py = me.getY();
repaint();
showStatus("Mouse Clicked");
}

}

WindowEvent example

2014-09-17T15:35:00.001+05:30

import java.awt.*;
import java.awt.event.*;

public class TestWindowEvent extends Frame implements WindowListener
{

public TestWindowEvent() {

setSize(400,500);
setVisible(true);

this.addWindowListener(this);

}

public void windowDeactivated(WindowEvent we) {
System.out.println("Deactivated" );
}

public void windowActivated(WindowEvent we) {
System.out.println("Activated" );
}

public void windowDeiconified(WindowEvent we) {
System.out.println("Deiconifid" );
}
public void windowIconified(WindowEvent we) {

System.out.println("Iconified" );
}
public void windowClosed(WindowEvent we) {
System.out.println("Closed" );
}
public void windowOpened(WindowEvent we) {
System.out.println("Opened" );
}
public void windowClosing(WindowEvent we) {
System.exit(0);
}

public static void main(String args[]) {

new TestWindowEvent();
}

}

Frame with ActionEvent

2014-09-17T15:34:00.000+05:30

import java.awt.*;
import java.awt.event.*;

public class TestEventFrame extends Frame implements ActionListener
{
Button bt, clearbt,addbt;
TextField tf1, tf2, tf3;
Label lno1, lno2;

public TestEventFrame() {
//creating components
bt = new Button("Close");
clearbt = new Button("Clear");
addbt = new Button("Add");
tf1 = new TextField(3);
tf2 = new TextField(3);
tf3 = new TextField(3);
tf3.setEditable(false);
lno1 = new Label("No1 :");
lno2 = new Label("No2 :");
//Adding Components
add(lno1); add(tf1); add(lno2); add(tf2); add(tf3);
add(bt);
add(addbt);
add(clearbt);
//registering listener
bt.addActionListener(this);
addbt.addActionListener(this);
clearbt.addActionListener(this);
//setting properties of Frame
setSize(400,500);
setVisible(true);
setTitle("First Frame");
setLayout(new FlowLayout());
}
public void actionPerformed(ActionEvent ae) {

if (ae.getSource().equals(bt))
{ System.exit(0); }
else if (ae.getSource().equals(addbt) )
{
String sno1 = tf1.getText();
String sno2 = tf2.getText();

int sum = Integer.parseInt(sno1) + Integer.parseInt(sno2);

//Integer iobj = Integer.valueOf(sum);
//String sums = iobj.toString();
tf3.setText(String.valueOf(sum));

}
else {
tf1.setText(""); tf2.setText(""); tf3.setText("");
}

}

public static void main(String args[]) {

//TestEventFrame tf =
new TestEventFrame();

}

}

Simple Swing Frame with closing functionality

2014-09-17T15:31:00.005+05:30

import javax.swing.*;

public class SwingWindowEvent extends JFrame
{

public SwingWindowEvent() {

setSize(400,500);
setVisible(true);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

public static void main(String args[]) {

new SwingWindowEvent();
}

}

Simple GUI AWT Frame

2014-09-17T15:30:00.001+05:30

import java.awt.*;
class MyFrame extends Frame {
private Button myb;
MyFrame() {
myb = new Button("OK");
setLayout(new FlowLayout());
add(myb);
setSize(200,300);
setTitle("First Frame");
setVisible(true);
}

}
public class MyFirstFrame {

public static void main(String args[])
{
// MyFrame f = new MyFrame();
new MyFrame();
}

}

Multiple Exception Example

2014-09-17T15:26:00.003+05:30

import java.util.Scanner;

public class MultipleTestException
{
/* exception example
*/
public static void main(String args[]) {
int no1=0, no2=0 ;
try {
no1 = Integer.parseInt(args[0]);
no2 = Integer.parseInt(args[1]);
System.out.println("After 2nd argument" );
}
catch (ArrayIndexOutOfBoundsException ae)
{
System.out.println(ae);
}
catch (NumberFormatException ne) {
System.out.println(ne);

}
finally {
System.out.println("Resources are released");
}

System.out.println("sum : " + (no1 + no2) );

try {
System.out.println("Division : " + (no1 / no2) );
}
catch (ArithmeticException ae)
{
System.out.println(ae.getMessage());
//System.out.println("Divide by Zero");
}

System.out.println("Difference : " + (no1 - no2) );

System.out.println("Multiplication : " + (no1 * no2) );

}

}

Exception Example

2014-09-17T15:26:00.000+05:30

import java.util.Scanner;

public class TestException
{
/* exception example
*/
public static void main(String args[]) {

Scanner sin = new Scanner(System.in);

System.out.println("Enter no1 :");

int no1 = sin.nextInt();
System.out.println("Enter no2 :");
int no2 = sin.nextInt();

System.out.println("sum : " + (no1 + no2) );

try {
System.out.println("Division : " + (no1 / no2) );
}
catch (ArithmeticException ae)
{

System.out.println("Divide by Zero");
}

System.out.println("Difference : " + (no1 - no2) );

System.out.println("Multiplication : " + (no1 * no2) );

}

}

Checkbox and List Example

2013-10-28T16:15:00.003+05:30

import java.awt.*;
import java.awt.event.*;

class MyChoiceCheckBoxExample extends MasterAWTFrame implements ItemListener
{
private Checkbox cbbold, cbitalic, cbred, cbblue, cbcyan, cbgray;
private Choice ch1;
private CheckboxGroup chg;
private TextArea ta;
private Font f;
private List mylist, myfsize;
private int style = Font.PLAIN; private String fname =Font.SANS_SERIF;
private int fontsize = 12;
private String sstr="";
private Canvas drawCan;
MyChoiceCheckBoxExample() {

cbbold = new Checkbox("Bold");
cbitalic = new Checkbox("Italic");
chg = new CheckboxGroup();

cbred = new Checkbox("Blue", chg, true);
cbgray = new Checkbox("Gray", chg, false);
cbcyan = new Checkbox("Cyan", chg, false);

drawCan = new Canvas(); drawCan.setBackground(Color.MAGENTA);

ta = new TextArea("ISTAR Institute VVNAGAR , ANAND, GUJARAT", 20, 100);
ta.setFont(new Font(fname,style,18));

mylist = new List(15);
mylist.addItemListener(this);
mylist.add(Font.MONOSPACED); mylist.add(Font.SERIF);
// mylist.add("Arial"); mylist.add("Times New Roman");
// getMySystemFont(mylist);

myfsize = new List(7); myfsize.add("10"); myfsize.add("12"); myfsize.add("14");
myfsize.add("18"); myfsize.add("22"); myfsize.add("24"); myfsize.add("30");
myfsize.addItemListener(this);

// mylist.add("Arial"); mylist.add("Times New Roman"); mylist.add("Calibri");
//mylist.add(Font.SANS_SERIF); mylist.add(Font.SERIF);
//mylist.add("Bookman Old Style"); mylist.add("Courier New");
p1.add(cbbold); p1.add(cbitalic);

p1.add(drawCan);

p1.add(cbred); p1.add(cbgray); p1.add(cbcyan);

p2.add(mylist); p2.add(myfsize); p2.add(ta);

mylist.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {
ta.setText(String.valueOf(mylist.getSelectedIndex()));
}
} );

cbbold.addItemListener(this);
cbitalic.addItemListener(this);

cbred.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {
if (e.getStateChange()== ItemEvent.SELECTED)
{
p1.setBackground(Color.blue);
}
}
});

cbgray.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {

if (e.getSource().equals(cbgray))
{
p1.setBackground(Color.gray);
}
}
});

cbcyan.addItemListener(new ItemListener() {

public void itemStateChanged(ItemEvent e) {
if (e.getStateChange()== ItemEvent.SELECTED)
{
p1.setBackground(Color.cyan);
}
}
});

}

public void paint(Graphics g)
{
g.drawString("Hello World", 120,200);
g.setFont(f);

}
public void getMySystemFont(List mylist)
{

GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
String strfont[] = ge.getAvailableFontFamilyNames();

for (String str: strfont) { mylist.add(str);
}

}

//item state changed method

public void itemStateChanged(ItemEvent e) {

// int style = Font.PLAIN;

if (e.getSource() instanceof Checkbox)
{
if (e.getSource().equals(cbbold))
{
if (e.getStateChange()== ItemEvent.SELECTED)
{

style +=Font.BOLD;
}
if (e.getStateChange()==ItemEvent.DESELECTED)
{
style -=Font.BOLD;
}
} // outer if BOLD

else if (e.getSource().equals(cbitalic)) {
if (e.getStateChange()== ItemEvent.SELECTED)
{
style += Font.ITALIC;
}
if (e.getStateChange()==ItemEvent.DESELECTED)
{
style -=Font.ITALIC;
}

} // outer if ITALIC

} // instance of Checkbox

if (e.getSource() instanceof List )
{

if (e.getSource().equals(mylist))
{
fname=mylist.getSelectedItem();
//System.out.println(mylist.getSelectedItem());

}

if (e.getSource().equals(myfsize))
{
fontsize = Integer.parseInt(myfsize.getSelectedItem());

}
}
//System.out.println("fname :"+ fname);
f = new Font(fname,style ,fontsize);
ta.setFont(f);
repaint();
System.out.println("f :" + f.getName());
System.out.println("font family : "+ f.getFamily());
System.out.println("font : "+ f.getFontName());

} // end of method

} // end of class

public class ChoiceMainClass {

public static void main(String[] args) {

new MyChoiceCheckBoxExample();//.getMySystemFont();

}
}

Exception Handling Example

2013-10-28T16:08:00.002+05:30

import java.io.IOException;

class MyException extends Exception
{
String mess;
public MyException(String message) {
super(message);
mess = message;
}

}

class MyTest
{
public static char read() throws IOException
{

char mychar = (char)System.in.read();

return mychar;
}
}
public class MyExceptionTest {

public static void main(String[] args) {

try {
throw new MyException("My First exception ");
}
catch(MyException me) {
System.out.println(me.getMessage());
// me.printStackTrace();
}

try {

char mych = MyTest.read();

System.out.println(mych);

}

catch (Exception e) {

e.printStackTrace();
}
System.out.println("here ");

}
}