抽象类和接口补充题

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1、下面的代码如有错误，请指出并加以改正。(1)abstractclassName{privateStringname;publicabstractbooleanisStupidName(Stringname){}//抽象方法不能有实现}(2)publicclassSomething{voiddoSomething(){privateStrings="";//局部变量之前不能放任何修饰符intl=s.length();}}(3)abstractclassSomething{privateabstractStringd

2、oSomething();//abstract,private不能同时修饰一个方法}(4)publicclassSomething{publicintaddOne(finalintx){return++x;}}//final定义的常量不能被修改(5)publicclassSomething{publicstaticvoidmain(String[]args){Othero=newOther();newSomething().addOne(o);}publicvoidaddOne(finalOthero){o.i+

3、+;}}classOther{publicinti;}//final定义的是一个方法，不是里面的变量，所以正确(6)classSomething{finalinti;//final定义的常量没有初始值publicvoiddoSomething(){System.out.println("i="+i);}}(7)publicclassSomething{publicstaticvoidmain(String[]args){Somethings=newSomething();System.out.pirntln("s

4、.doSomething()returns"+doSomething());}publicStringdoSomething(){return"Dosomething...";}}//静态方法中不能直接调用类的成员方法(8)interfaceA{intx=0;}classB{intx=1;}classCextendsBimplementsA{publicvoidpX(){System.out.println(x);//x的用意不明显，不知道调用的是A还是B的x}publicstaticvoidmain(Strin

5、g[]args){newC().pX();}}(9)interfacePlayable{voidplay();}interfaceBounceable{voidplay();}interfaceRollableextendsPlayable,Bounceable{Ballball=newBall("Pingpang");//相当于publicstaticfinal，之后不能再修改}publicclassBallimplementsRollable{privateStringname;publicBall(Stri

6、ngname){this.name=name;}publicvoidplay(){ball=newBall("Football");System.out.println(ball.getName());}publicStringgetName(){returnname;}publicstaticvoidmain(String[]args){}}