Why should I use anonymous-classes?

Question

What should be the reason to override an method with an anonymous class?
I do not see the advantage.

Answer 1

Hello Tim Suchland

Expect for GUI programs I've never used anonymous classes.
In principle you can use them if you need an interface or abstract class only for a single object.

To stick with GUI. Imagine a Button. If you click this Button something should happen. For this you need the Interface ActionListener. But you know only the Button object needs this. (There are some more reasons but I want to keep it very easy).
You don't want to implement the ActionListener for the whole class. And you don't want to write a normal extra class.

Here you can use an anonymous class.

A tiny javafx example:

Button btn = new Button();
btn.setOnAction(new ActionListener(){

@Override
public void actionPerformed{

//the stuff which should happen when you click the Button

}

});

Since java 8 you can use lambda expressions so you have a small compact anonymous class.

As you can see, the anonymous class has no name and no meaning outside the Button method.

To be continued...

Answer 2

Part 2:

If you want the Button has it's own class which is tailored to it. And you don't need to think about it anymore.

Answer 3

Thanks Denise Roßberg for the answer. This helps me to understand the concept better. My only feeling is, that this is not the best coding style.