Java inheritance: How to achieve something similar to "multiple inheritance" when it is not allowed in Java?

Question

This is a question mostly about Java inheritance. I am developing a program which has 2 windows, both of which will be developed in separate classes which will extend JPanel. The first class is "FileSub1" and the second one is "FileSub2".

There are a lot of methods that are common to these two classes, so I would like to create a class called "Files" and make "FileSub1" and "FileSub2" its subclasses. But Java doesn't support multiple inheritance! What can I do here?

Answer 1

Prefer Composition over Inheritance

Include a FileThing in your JPanel subclass, instead of making it a FileThing and a JPanel.