super和extends從字面上來說的話是父類引用和子類繼承的關(guān)系垮衷，所以如下所示：
（1）is any class which is as uper class?of String(including String itself). (In this case, the only other suitable class isObject.)
即包括String的父類和它本身的String類照激。
（2）(which in this specific case wouldn't be very useful as Stringis final, so it can have no subclasses).
即包括String的子類，而String沒有子類属桦，為null和二。
