从Eclipse提示信息看问题(last edit by 2010,01.20)

 

1.This static method cannot hide the instance method from [superclass]

父类的实例方法,子类不允许用同名且同参数的静态方法隐藏.

e.g:

superclass >public void printCCTV (int a, int b)

subclass    >public static void printCCTV (int a, int b)  ----------------false

subclass    >public static void printCCTV (int a, long b)  --------------true(change args)

subclass    >public void printCCTV (int a, long b)         ----------------true(change args and return type)

 

2.The return type is incompatible with  [supercalss].[method]

子类中该方法的返回值必须与父类同名同参数方法返回值保持一致

e.g:

superclass >public static void printCCTV (int a, int b)

subclass    >public static void printCCTV (int a, int b)  ----------------true//动态绑定该静态方法

subclass    >public static int printCCTV (int a, int b)     ----------------false

subclass    >public static int printCCTV (int a, long b)  ----------------true(change args)

 

 

3.This instance method cannot override the static method from[class]

实例方法不允许重载静态方法.

e.g:

superclass >public static void printCCTV (int a, int b)

subclass    >public void printCCTV (int a, int b)            ----------------false

subclass    >public static void printCCTV (int a, int b)  ----------------true

subclass    >public static void printCCTV (int a, long b)  --------------true

 

4.Cannot reduce the visibility of the inherited method from [superclass]

不可进一步缩小继承而来的方法的可见性.(public > protected > default  > private)

e.g:

superclass >protected void printCCTV (int a, int b)

subclass    >public void printCCTV (int a, int b)            ----------------false

subclass    >public void printCCTV (int a, int b)            ----------------false

 

superclass >private void printCCTV (int a, int b)

subclass    >private void printCCTV (int a, int b)           ----------------true

subclass    >public   void printCCTV (int a, int b)           ----------------true

 

superclass >void printCCTV (int a, int b)

subclass    >void printCCTV (int a, int b)                       ----------------true(default)

subclass    >private void printCCTV (int a, int b)           ----------------false

subclass    >public   void printCCTV (int a, int b)           ----------------true