Multiple inheritance for an anonymous class

Anonymous classes must extend or implement something, like any other Java class, even if it's just java.lang.Object.

For example:

Runnable r = new Runnable() {   public void run() { ... }};

Here, r is an object of an anonymous class which implements Runnable.

An anonymous class can extend another class using the same syntax:

SomeClass x = new SomeClass() {   ...};

What you can't do is implement more than one interface. You need a named class to do that. Neither an anonymous inner class, nor a named class, however, can extend more than one class.

An anonymous class usually implements an interface:

new Runnable() { // implements Runnable!   public void run() {}}JFrame.addWindowListener( new WindowAdapter() { // extends  class} );

If you mean whether you can implement 2 or more interfaces, than I think that's not possible. You can then make a private interface which combines the two. Though I cannot easily imagine why you would want an anonymous class to have that:

 public class MyClass {   private interface MyInterface extends Runnable, WindowListener {    }   Runnable r = new MyInterface() {    // your anonymous class which implements 2 interaces   } }

Anonymous classes always extend superclass or implements interfaces. for example:

button.addActionListener(new ActionListener(){ // ActionListener is an interface    public void actionPerformed(ActionEvent e){    }});

Moreover, although anonymous class cannot implement multiple interfaces, you can create an interface that extends other interface and let your anonymous class to implement it.