Исходные тексты аплета Rectangles приведены в листинге 1.

Листинг 1. Файл Rectangles,java

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

 public class Rectangles extends
Applet { DrawRectangles m_DrawRectThread = null; DrawEllipse m_DrawEllipseThread
= null; NotifyTask m_NotifyTaskThread = null

public String getAppletInfo() { return "Name: Rectangles"; }

public void paint(Graphics g) { Dimension dimAppWndDimension = getSize();

g.setColor(Color.yellow); g.fillRect(0, 0, dimAppWndDimension.width - 1, dimAppWndDimension.height
- 1);

 g.setColor(Color.black); g.drawRect(0,
0, dimAppWndDimension.width - 1, dimAppWndDimension.height - 1); }

public void start() { if (m_DrawRectThread == null) { m_DrawRectThread = new DrawRectangles(this);
m_DrawRectThread.start(); }

 if (m_DrawEllipseThread
== null) { m_DrawEllipseThread = new DrawEllipse(this); m_DrawEllipseThread.start();
}

 if (m_NotifyTaskThread == null) { m_NotifyTaskThread
= new NotifyTask(m_DrawEllipseThread); m_NotifyTaskThread.start(); } } public
void stop() { if (m_DrawRectThread != null) { m_DrawRectThread.stop(); m_DrawRectThread
= null; }

 if (m_DrawEllipseThread == null)
{ m_DrawEllipseThread.stop(); m_DrawEllipseThread = null; } 

if (m_NotifyTaskThread != null) { m_NotifyTaskThread.stop(); m_NotifyTaskThread
= null; } } }

class DrawRectangles extends
Thread { Graphics g; Dimension dimAppWndDimension;

public DrawRectangles(Applet Appl) { g = Appl.getGraphics(); dimAppWndDimension
= Appl.getSize(); }

 public void run()
{ while (true) { int x, y, width, height; int rColor, gColor, bColor; 

x = (int)(dimAppWndDimension.width * Math.random()); y = (int)(dimAppWndDimension.height
* Math.random()); width = (int)(dimAppWndDimension.width * Math.random()) / 2;
height = (int)(dimAppWndDimension.height * Math.random()) / 2; 

rColor = (int)(255 * Math.random()); gColor = (int)(255 * Math.random()); bColor
= (int)(255 * Math.random());

 g.setColor(new
Color(rColor, gColor, bColor)); g.fillRect(x, y, width, height);

try { Thread.sleep(50); } catch (InterruptedException e) { stop(); } } } }

class
DrawEllipse extends Thread { Graphics g; Dimension dimAppWndDimension;

public DrawEllipse(Applet Appl) { g = Appl.getGraphics(); dimAppWndDimension =
Appl.getSize(); }

 public synchronized
void run() { while (true) { int x, y, width, height; int rColor, gColor, bColor;

x = (int)(dimAppWndDimension.width * Math.random()); y = (int)(dimAppWndDimension.height
* Math.random()); width = (int)(dimAppWndDimension.width * Math.random()) / 2;
height = (int)(dimAppWndDimension.height * Math.random()) / 2;

rColor = (int)(255 * Math.random()); gColor = (int)(255 * Math.random()); bColor
= (int)(255 * Math.random());

 g.setColor(new
Color(rColor, gColor, bColor)); g.fillOval(x, y, width, height);

try { this.wait(); } catch (InterruptedException e) { } } } }

class
NotifyTask extends Thread { Thread STask;

public NotifyTask(Thread SynchroTask) { STask = SynchroTask; }

public void run() { while (true) { try { Thread.sleep(30); } catch (InterruptedException
e) { }

 synchronized(STask) { STask.notify();
} } } }