java CharSequence接口

1）CharSequence接口重新定义了toString()方法，这就要求实现类必须重写object中的toString()方法

String toString()Returns a string containing the characters in this sequence in the same order as this sequence. The length of the string will be the length of this sequence. 

Overrides: 
toString in class Object 
Returns:
a string consisting of exactly this sequence of characters

我们在实现时，如果定义接口时，我们对Object类中的一些方法不满意是，可以在接口中要求子类重写。