Cross.java

import java.awt.*;
public class Cross
{
    // instance variables - replace the example below with your own
    private int x, y, size;
    private Color color;

    /**
     * Constructor for objects of class Cross
     */
    public Cross(int x, int y,int size)
    {
       this.x=x;
       this.y=y;
       this.size=size;
       this.color = new Color (200,40,60);
    }

    public void paint(Graphics g)
    {
        g.setColor(color);
        g.fillRect(x+size/4, y, size/2,size);
        g.fillRect(x, y+size/4, size, size/2);

    }
}

Animate1.java

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

public class Animate1 extends JApplet implements ActionListener
{
    // instance variables - 
    private Timer timer;
    private int x;
    private Cross cross;

    public void init()
    {
        // this is a workaround for a security conflict with some browsers
        // including some versions of Netscape & Internet Explorer which do 
        // not allow access to the AWT system event queue which JApplets do 
        // on startup to check access. May not be necessary with your browser. 
        JRootPane rootPane = this.getRootPane();    
        rootPane.putClientProperty("defeatSystemEventQueueCheck", Boolean.TRUE);

        // provide any initialisation necessary for your JApplet here
        Timer timer = new Timer(100, this);
        x=0;
        timer.start();
        cross = new Cross(100, 50, 70);

    }

    /**
     * Paint method for applet.
     * 
     * @param  g   the Graphics object for this applet
     */
    public void paint(Graphics g)
    {
        // simple text displayed on applet
        g.setColor(Color.white);
        g.fillRect(0, 0, 500, 500);
        g.setColor(Color.black);
        g.drawString("Animate", 20, 20);
        g.setColor(Color.blue);
        g.drawString("x is now "+x, 20, 40);
        cross.paint(g);
    }

    public void actionPerformed(ActionEvent e) {
        x++;
        x%=100;
        repaint();
    }

}

We will get the object moving by defining a Moveable interface which needs a move method. The idea is we might have many other objects that will be moveable and they can each implement their own move method to move the way they want to.

1. Make the Moveable interface
2. Change Cross so that it implements the Moveable interface so it moves one to the right
3. Change Animate to activate the move method of the cross when the timer sends its ActionEvent
4. Make a new class (like Box) that also implements the Moveable interface
5. Make an ArrayList that can contain the different Moveable objects so you can make a loop to execute all their move methods