
Composing an applet of a class which extends Thread: 
This example uses two different classes which
extend Thread. Each class has the ability to paint itself (this is done
in the run() method). Also the applet class is composed of arrays
of the two thread classes.





import java.awt.*;
import java.applet.*;

public class move extends Applet {
  vert[] v;
  horiz[] h;

  public void init() {
    setBackground(Color.cyan);
    v = new vert[9];
    h = new horiz[9];
    for(int i=0; i<v.length; i++) {
      v[i]=new vert(i*20+20,getGraphics());
      h[i]=new horiz(i*20+20,getGraphics());
    }
  }
}

class vert extends Thread {
  Graphics g;
  int x;

  vert(int i, Graphics gr) {
    x=i;
    g=gr;
    this.start();
  }

  public void run() {
    int pos=0;
    int inc=10;
    while(true) {
      if(inc==10) g.setColor(Color.red);
      else g.setColor(Color.green);
      g.fillRect(x, pos, 10,10);
      pos+=inc;
      if(pos>220 || pos<0) inc*=-1;
      try{
        this.sleep(200);
      }catch(InterruptedException e){}
    }
  }
}

class horiz extends Thread {
  Graphics g;
  int y;

  horiz(int i, Graphics gr) {
    y=i;
    g=gr;
    this.start();
  }

  public void run() {
    int pos=0;
    int inc=10;
    while(true) {
      if(inc==10) g.setColor(Color.blue);
      else g.setColor(Color.yellow);
      g.fillRect(pos, y, 10,10);
      pos+=inc;
      if(pos>220 || pos<0) inc*=-1;
      try{
        this.sleep(200);
      }catch(InterruptedException e){}
    }
  }
}