1. abstract class
abstract class can have anything a normal class can have plus abstract method
public abstract class Test11 { public int a; private int b; public abstract void f1(); public void f2() { } }
2. interface
only variable and abstract method,
can extends another interface,
cannot extends class or implement interface
public interface Inter2 extends Inter1 { public int a = 1; public abstract void f1(); public void f2(); }
原文：http://www.cnblogs.com/phoenix13suns/p/4084383.html