实例化匿名类时可以实现接口吗？

Question

Suppose I have an abstract class FactorizedDialog . It looks like this (please note that this is just some dummy example)

public abstract class FactorizedDialog extends Dialog {

  public abstract void myMethod();
} 

Now I can do something like this:

FactorizedDialog dialog = new FactorizedDialog() {

            @Override
            public void myMethod() {
                // implementation here
            }
}

As you may have guessed I extend Dialog (which is in fact an abstract class) only to add a method to it so I can override it when I create an anonymous class. Is it possible to implement an interface in java while I instantiate Dialog instead of using my derived abstract class?

Answer 1

No, when you specify the superclass of an anonymous inner class you can either specify a normal class to extend or an interface, but not both. The syntax shown in section 15.9 of the JLS simply doesn't allow for both.

Answer 2

If you mean the below where Dialog is an interface, then yes it can be done.

Dialog dialog = new Dialog() {

    @Override
    public void myMethod() {
    }
}

Of course then the declaration of myMethod should go into the Dialog interface.