空抽象类的用途是什么？

Question

I want to know that is there any use of empty abstract class in Java? If so, what is it?

Answer 1

An empty abstract class is very much equivalent to an interface except that it can extend a class

abstract class myAbstractClass // extends anotherClass implements anInterface
{

}

interface myInterface // extends anotherInterface
{

}

This pattern is called Marker interface and SO has a lot of good data about it already: What is the purpose of a marker interface?

Answer 2

you can only inherit from one abstract class. Then this is useful to avoid inheritance.

Answer 3

是的，有时你需要一个实现多态的基类。