Miscellany

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class Evolution extends JFrame implements ActionListener {
	private PlayPanel myPlayPanel;
	public Individual[] individuals;
	private Timer tim = new Timer(20, this);
	
	
	
	public Evolution () {
		
		setTitle("Myror");
		setSize(600,600);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		Container c = getContentPane();
		c.setLayout(new BorderLayout());
		myPlayPanel = new PlayPanel();
		c.add(myPlayPanel, BorderLayout.CENTER);
		tim.start();
		setVisible(true);
		
		individuals = new Individual[100];
		for(int i=0;i<100;i++) {
			individuals[i] = new Individual(100,200,0, false);
		}
	}
	
	public void actionPerformed (ActionEvent e) {
		for(int i=0;i<100;i++) {	
			individuals[i].step();	
		}
		repaint();
	}
	
	public static void main(String[] args) {
		new Evolution();
	}
	
	public class PlayPanel extends JPanel {
		public void paintComponent(Graphics g) {
			super.paintComponent(g);
			g.setColor(Color.black);
			g.drawRect(0, 0, 600, 600);
			g.fillRect(0, 0, 600, 600);
			for(int i=0;i<100;i++) {	
				individuals[i].draw(g);	
			}
		}
	}
}



Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at Evolution.actionPerformed(Evolution.java:32)
	at javax.swing.Timer.fireActionPerformed(Unknown Source)
	at javax.swing.Timer$DoPostEvent.run(Unknown Source)
	at java.awt.event.InvocationEvent.dispatch(Unknown Source)
	at java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.run(Unknown Source)