接口中的内部类

在接口中实现内部类可以使该接口的所有实现所共用。

public interface BaseInter {
    public void f1();
    public void f2();

    class BaseImp implements BaseInter{

        @Override
        public void f1() {
            System.out.println("Base.f1()");
        }

        @Override
        public void f2() {
            System.out.println("Base.f2()");
        }

    }
}

public interface BusinessInter1 extends BaseInter {
    public void businessFun1();
}

public class BusinessImp extends BusinessInter1.BaseImp implements BusinessInter1 {

    public static void main(String[] args) {
        BusinessImp bi=new BusinessImp();
        bi.f1();

    }

    @Override
    public void businessFun1() {
        System.out.println("businessFun1");
    }
}

注：放入接口中的任何类都自动是public和static的。