CC150第14章JAVA总结 to be continued

1.In terms of inheritance, what is the effect of keeping a constructor private?

cannot instantiate the class directly.

cannot be inherited.

不能被继承，实例化只能在类内构造静态方法

2.In Java, does the finally block gets executed if we insert a return statement inside thetry block of a try-catch-finally? 

Yes, no matter using return, continue or break, the finally block will be executed.

3.What is the difference between final, finally, and finalize? 

        final:variable:value cannot be changed

                 method:cannot be overridden

                class:cannot be subclassed

        finally: be used in try/catch block

       finally: method that be executed before running the garbage collector

4. to be continued

5.to be continued

6. 如何在使用MAP是加上对put()和get()的计数功能。

重写MAP的put()和get()，使用静态变量计数

class Mapp<K,V> extends HashMap<K,V>{
    static int num;
    @Override
    public V get(Object k){
        num++;
        return super.get(k);
    }
}