Start: applet not initialized

[Radhika Srinivasan]

Write an applet that implements the runnable interface that will simulate a yo-yo going up & down on a string. To reduce flickers, repaint only the string and YO-YO in the back ground color.

Kindly help me sort out the error.

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

public class YoYo extends Applet implements Runnable
{
	int x = 140;
	int y = 150;
                private int sleep = 100;
	
	Thread yoyo;
	
	int oldy;
	int increment = 10;
	boolean falling = true;
	int counter = 0;

	public void init()
	{
		if(yoyo == null)
		{
		yoyo = new Thread(this);
		yoyo.start();
		}
	}
	
	public void run()
	{
	Graphics g = getGraphics();
	while(true)
	{
	oldy = y;
	try
	{
	yoyo.sleep(100);
	}
	catch(InterruptedException e)
	{
	}
	counter++;
	
	if(counter > 10 && falling)
	{
	falling = false;
	counter =0;
	}
	
	if(counter >10 && !falling)
	{
	falling = true;
	counter = 0;
	}
	
	g.setColor(Color.white);
	g.drawLine(150,100,150, oldy);
	g.setColor(Color.white);
	g.fillOval(140,oldy,20,20);
	
	if(falling) y = oldy + increment;
	else y = oldy - increment;
	
	g.setColor(Color.red);
	g.drawLine(150,100,150,y);
	g.setColor(Color.green);
	g.fillOval(140,y,20,20);
	}
 }
 
         public void update(Graphics g)
	{
		paint(g);
	}

	public void paint(Graphics g)
	{
	setBackground(Color.white);
	
	g.setColor(Color.blue);
	g.drawOval(100,30,100,80);
	g.drawLine(150,110,150,210);
	g.drawLine(150,210,90,310);
	g.drawLine(150,210,190,310);

	g.drawLine(150,140,60,140);
	g.drawLine(150,140,240,140);
	g.drawLine(60,140,60,200);
	g.setColor(Color.red);
	g.fillOval(50,200,20,20);
	g.setColor(Color.blue);
	g.drawLine(240,140,240,200);
	g.setColor(Color.green);
	g.fillOval(230,200,20,20);
                
                try{
                  Thread.sleep(sleep);}
                catch(InterruptedException e){}
                repaint();
	
	}
}

[Ulf Dittmer]

Welcome to JavaRanch.

Please edit your post to UseCodeTags. It's unnecessarily hard to read the code as it is, making it less likely that people will bother to do so.

Also post the applet tag you're using and any exception that's in the Java Console (I'm fairly certain that there is one).