Java中的多重继承：实现接口

Question

I have a class that implements Comparator but not that I need my class to be Serializable How can I implement both of them ?

public class A implements Comparator<A>
{
}

Answer 1

It's a common misconception that Java does not have multiple inheritance. It doesn't have multiple inheritance of state, but it does have multiple inheritance of (declarations of) behavior, which is shown through interfaces. So you can have a single class implement multiple interfaces:

public class A implements Comparator<A>, Serializable {
}

Answer 2

import java.io.Serializable;
import java.util.Comparator;

public class A implements Comparator<A>, Serializable {

    @Override
    public int compare(A arg0, A arg1) {
        return 0;
    }
}

Answer 3

You can implement more than one interface, simply separate them with commas:

class A implements Comparator<A>, Serializable {
}

Answer 4

You can extend only one superclass but you can implement as many interfaces as you like, eg

public class A extends B implements Comparator<A>, Serializable {
}