类B:
public interface B {
public void methodD();
}
------------------------------------
类A:
public abstract class A implements B{
abstract void methodA();
abstract void methodB();
abstract void methodC();
public void methodD(){
methodC();
methodB();
methodA();
}
}
--------------------------------------
类D:
public class D extends A {
void methodA() {
// TODO Auto-generated method stub
System.out.println("方法A");
}
void methodB() {
// TODO Auto-generated method stub
System.out.println("方法B");
}
void methodC() {
// TODO Auto-generated method stub
System.out.println("方法C");
}
}
----------------------------------------
类C:
public class C{
public B methodE(){
B c=new D();
return c;
}
}
这个类到底怎么理解呢?
-------------------------------------
public class Test {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
C d=new C();
B c=d.methodE();
c.methodD();
}
}
上面类C里的: B c=new D(); 这到底怎么回事呢?不是父类与子类之间才可以这样的吗?现在这样是什么意思呢?