Writing Applets With Threads in Advanced Java Programming

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You can create threads that can be implemented using applet. The following program code shows how to execute a moving banner based on applet using threads. The banner moves form right to left in a horizontal manner. Consider the code:

/* =========================================================== File Name : ThreadApplet.java WebSite : http://javaproglang.blogspot.in/ Facebook : https://www.facebook.com/AdvanceJavaProgramming Twitter ID : https://twitter.com/AdvanceJava Created By : Bintu Chaudhary =========================================================== */ import java.awt.*; import java.applet.*; /* <applet code="ThreadApplet" width=500 Height=100> </applet> */ public class ThreadApplet extends Applet implements Runnable { String message="This is an example of working with threads in an applet."; Thread thread1=null; int status; boolean flag; public void init() { setBackground(Color.green); setBackground(Color.red); } public void start() { thread1=new Thread(this); flag=false; thread1.start(); } public void run() { char c; for(; ;) { try { repaint(); Thread.sleep(400); c=message.charAt(0); message=message.substring(1,message.length()); message+=c; if(flag) { break; } } catch(InterruptedException e) { } } } public void stop() { flag=true; thread1=null; } public void paint(Graphics g) { g.drawString(message,50,50); } }

In the above example, the ThreadApplet class is created that extends the applet and implements the runnable interface to execute threads in an applet. In the above example, you create an object of the thread class with a Thread1. The init method is used to initialise the foreground colour and background colour of the applet. The applet start method is used to create and execute the first thread. The second thread method is required to repaint the applet screen each time the message string is scrolled horizontally from right to left. The stop method is used to stop the execution of the thread.

The above code will be stored in the file called ThreadApplet.java, which on compilation will crate a class file called ThreadApplet.class. Now compile this file using below commands in the DOS mode:

C:\>jdk1.4\bin>javac ThreadApplet.java
C:\>jdk1.4\bin>appletviewer ThreadApplet.java

"Output of ThreadApplet.class"

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MultiThreading

Thread Life Cycle	Main Thread
Creating A Thread	Thread Priority
Extending The Thread Class	Writing Applets With Threads