Implements MyClass extends JFrame

[coco]

Hi, Can someone tell me what is implements mean??

Code:

import java.awt.*;
import java.awt.event.*;
public class MyClass extends JFrame implements ActionListener{

I understand what extends mean (super class and sub class), but what is implements mean?
Thanks.

[hardwired]

implements is for interfaces as opposed to classes which we extend.
When a class implements an interface it must provide an implementation of each and every method defined by the interface. The implementation can be empty but the method signature must appear inside the class.
Examples:

Code:

public class MyClass extends JFrame implements ActionListener {
    public void actionPerformed(ActionEvent e) {
    }
}

public class Pseudo implements Runnable {
    public void run() {
    }
}

class Pseudo implements MouseMotionListener {
    public void mouseDragged(MouseEvent e) {
        // code for dragging in this component
    }

    public void mouseMoved(MouseEvent e) {
        // empty implementation - no code
    }
}

You can look up the interface in the api/javadocs to see which methods are defined.