package com.xdf.exam;
public class A {
public String show(D d) { return " A ADN D"; }
public String show(A a) { return " A ADN A"; }
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package com.xdf.exam;
public class B extends A {
public String show(B b) { return " B ADN B"; }
public String show(A a) { return " B ADN A"; }
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package com.xdf.exam;
public class Demo {
public static void main(String[] args) { A a1 = new A(); A a2 = new B(); B b = new B(); C c = new C(); D d = new D(); System.out.println("以下的输出结果："); /** * A类中有方法show(A a) * B是A的子类 */ System.out.println(a1.show(b)); // A ADN A /** * A类中有方法show(A a) * C类的父类是B类 * B类的父类是A类 */ System.out.println(a1.show(c));// A ADN A System.out.println(a1.show(d));// A ADN D /** * a2是父类的引用指向了子类B的对象 * 01.先去A类中查询show()并且参数是B类型的 * 02.发现没有 但是有show(A a) * 03.因为B类中重写了show(A a) * 所以执行B类的show(A a) */ System.out.println(a2.show(b));// B ADN A System.out.println(a2.show(c));// B ADN A System.out.println(a2.show(d));// A ADN D System.out.println(b.show(b));// B ADN B System.out.println(b.show(c));// B ADN B System.out.println(b.show(d));// A ADN D