Question

Suppose I have a class A:

public class A {
    public A(){....}
    public void method1() {...}
};

And an instance of that class:

A anA = new A();

Is there any way to override the method1() only for anA?
This question arises when I write a small painting program in which I have to extend the JPanel class several times just to make minor changes to the different panels that have slightly different characteristics.

Answer 1

You can do the following:

A anA = new A() {
    public void method1() {
        ...
    }
};

This is the same as:

private static class myA extends A {
    public void method1() {
        ...
    }
}

A anA = new myA();

Only with the exception that in this case myA can be reused. That’s not possible with anonymous classes.