The following program will create two Thread objects and display two messages interchangeably
public class ThreadDemo{
public static void main(String[] arg){
Message m1 = new Message("SriLanka win");
Thread t1 = new Thread(m1);
Message m2 = new Message("Australia win");
Thread t2 = new Thread(m2);
t1.start();
t2.start();
}
}
class Message implements Runnable{
public String msg;
public Message(String s){
msg=s;
}
public void run(){
for(int i=0;i<100;i++)
System.out.println(msg);
}
}
The following program draw Archs in an applet and uses a thread to refresh the browser
import java.applet.*;
import java.awt.*;
import java.util.*;
public class ArcDemo extends Applet implements Runnable {
int k=0, x=0;
Thread t;
Color col[] = new Color[50];
public void init() {
float h = 0.0f;
for(int i=0; i<col.length;i++) {
col[i] = Color.getHSBColor(h,1.0f,1.0f);
h+=0.02;
}
}
public void start() {
if (t==null) {
t = new Thread (this);
t.start();
}
}
public void run() {
while (true) {
repaint();
setForeground(col[k]);
k++;
if(k==col.length) k=0;
x+=1; if(x==360) x=0;
try {
Thread.sleep(10);
} catch (InterruptedException e) {}
}
}
public void stop() {
if (t!=null) {
t = null;
}
}
public void paint (Graphics g) {
g.drawArc(100,100,400,400,0,x);
g.drawArc(125,125,350,350,0,x);
g.drawArc(150,150,300,300,0,x);
g.drawArc(175,175,250,250,0,x);
g.drawArc(200,200,200,200,0,x);
g.drawArc(225,225,150,150,0,x);
g.drawArc(250,250,100,100,0,x);
g.drawArc(275,275,50,50,0,x);
g.drawArc(298,298,5,5,0,x);
}
}
HTML code to display the above applet
<html>
<body>
<applet code="ArcDemo.class" width=600 height=600>
</applet>
</body>
</html>
Example 02:
import java.applet.*;
import java.awt.*;
import java.util.*;
public class ArcDemo2 extends Applet implements Runnable {
int k=0, x=0;
Thread t;
Color col[] = new Color[50];
public void init() {
float h = 0.0f;
for(int i=0; i<col.length;i++) {
col[i] = Color.getHSBColor(h,1.0f,1.0f);
h+=0.02;
}
}
public void start() {
if (t==null) {
t = new Thread (this);
t.start();
}
}
public void run() {
while (true) {
repaint();
setForeground(col[k]);
k++;
if(k==col.length) k=0;
x+=1; if(x==360) x=0;
try {
Thread.sleep(10);
} catch (InterruptedException e) {}
}
}
public void stop() {
if (t!=null) {
t = null;
}
}
public void paint (Graphics g) {
g.fillArc(100,100,400,400,0,x);
}
}
Analog Clock:
import java.applet.*;
import java.awt.*;
import java.util.*;
import java.awt.Graphics.*;
public class ClockDemo extends Applet implements Runnable {
int k=0, x=90, y=90, z=90;
Thread t;
Color col[] = new Color[50];
public void init() {
float h = 0.0f;
for(int i=0; i<col.length;i++) {
col[i] = Color.getHSBColor(h,1.0f,1.0f);
h+=0.02;
}
}
public void start() {
if (t==null) {
t = new Thread (this);
t.start();
}
}
public void run() {
while (true) {
repaint();
x-=5; if(x==0) x=360;
if(x==90) {
y-=5; if(y==0) y=360;
if(y==90) {
z-=5; if(z==0) z=360;
}
}
try {
Thread.sleep(1000);
} catch (InterruptedException e) {}
}
}
public void stop() {
if (t!=null) {
t = null;
}
}
public void paint (Graphics g) {
g.drawArc(100,100,400,400,0,390);
Font f = new Font("Times New Roman",Font.BOLD,30);
g.setFont(f);
g.setColor(Color.RED);
g.fillArc(105,105,390,390,x,2);
g.setColor(Color.BLACK);
g.fillArc(105,105,390,390,y,2);
g.fillArc(125,125,350,350,z,2);
g.fillArc(295,295,10,10,0,360);
g.drawString("12",287,130);
g.drawString("6",293,485);
g.drawString("9",120,310);
g.drawString("3",475,310);
}
}
HTML Code to display the above Applet
<html>
<body>
<applet code="ClockDemo.class" width=600 height=600>
</applet>
</body>
</html>
A Ball bumping up and down
Images used in the program
 |
| Ball2 |
 |
| Ball3 |
 |
| Ball1 |
 |
| Ball4 |
import java.applet.*;
import java.awt.*;
import java.util.*;
import java.awt.Graphics.*;
public class Ball extends Applet implements Runnable {import java.awt.*;
import java.util.*;
import java.awt.Graphics.*;
int k=0, y=0, x=0;
Thread t;
Image img[] = new Image[4];
public void init() {
for(int i=0; i<4; i++)
img[i] = this.getImage(this.getDocumentBase(),"Ball"+(i+1)+".GIF");
}
public void start() {
if (t==null) {
t = new Thread (this);
t.start();
}
}
public void run() {
while (true) {
repaint();
if((x<250 && x>230) || (x<280 && x>260)) {
k++; if(k==img.length) k=0;
}
//k++; if(k==img.length) k=0;
y+=2; x+=10;
if(x==500) {
while(x!=0) {
repaint();
if((x<250 && x>230) || (x<280 && x>260)) {
k++; if(k==img.length) k=0;
}
y+=2; x-=10;
try {
Thread.sleep(40);
} catch (InterruptedException e) {}
}
}
if(y==800) {
while(y!=0) {
repaint();
if((x<250 && x>230) || (x<280 && x>260)) {
k++; if(k==img.length) k=0;
}
y-=2; x+=10;
if(x==500) {
while(x!=0) {
repaint();
if((x<250 && x>230) || (x<280 && x>260)) {
k++; if(k==img.length) k=0;
}
y-=2; x-=10;
try {
Thread.sleep(40);
} catch (InterruptedException e) {}
}
}
try {
Thread.sleep(40);
} catch (InterruptedException e) {}
}
}
try {
Thread.sleep(40);
} catch (InterruptedException e) {}
}
}
public void stop() {
if (t!=null) {
t = null;
}
}
public void paint (Graphics g) {
g.drawImage(img[k],y,x,this);
}
}
