I was using getSize().width and getSize().height. Now I discovered that you can just use getWidth() and getHeight() for getting the applet width and height. Below in the sourcecode I am using these commands.
package test001;
import java.awt.*;
import java.applet.*;
public class testing001 extends Applet implements Runnable {
// Graphics for double buffering.
Graphics bufferGraphics;
Image offscreen;
public void init() {
setBackground(Color.black);
offscreen = createImage(getWidth(),getHeight());
bufferGraphics = offscreen.getGraphics();
new Thread(this).start();
}
public void run() {
for(;;) { // animation loop never ends
repaint();
try {
Thread.sleep(16);
}
catch (InterruptedException e) {
}
}
}
public void update(Graphics g){
bufferGraphics.clearRect( 0 , 0 , getWidth() , getHeight() );
bufferGraphics.setColor( Color.red );
bufferGraphics.drawString( "getWidth() and getHeight()" , 10 , 10 );
bufferGraphics.drawRect( 20 , 20 , getWidth()-40 , getHeight()-40 );
g.drawImage(offscreen,0,0,this);
}
}