多选题public class Parent {     int change() {…}     }  class Child extends Parent {     }  Which methods can be added into class Child?()Apublic int change(){}Bint chang(int i){}Cprivate int change(){}Dabstract int chang(){}

多选题
public class Parent {     int change() {…}     }  class Child extends Parent {     }  Which methods can be added into class Child?()
A

public int change(){}

B

int chang(int i){}

C

private int change(){}

D

abstract int chang(){}


参考解析

解析: 这个题目的问题在第35题中有详尽的叙述。需要注意的是答案D的内容,子类可以重写父类的方法并将之声明为抽象方法,但是这引发的问题是类必须声明为抽象类,否则编译不能通过,而且抽象方法不能有方法体,也就是方法声明后面不能带上那两个大括号({}),这些D都不能满足。

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单选题What produces a compiler error?()A class A { public A(int x) {} }B class A {} class B extends A { B() {} }C class A { A() {} } class B { public B() {} }D class Z { public Z(int) {} } class A extends Z {}