// // CORRECT, SOMEWHAT BETTER DESIGN (but still code duplication) // class A { public int a; public A(int i) { a = i;} public boolean equals(Object o) { return ((getClass() == o.getClass()) && (a == ((A) o).a)); } } class B extends A { public int b; public B(int i, int j) {super(i); b = j;} public boolean equals(Object o) { return ((getClass() == o.getClass()) && (b == ((B) o).b) && (a == ((B) o).a)); } } class C extends B { public int c; public C(int i, int j, int k) {super(i,j); c = k;} public boolean equals(Object o) { return ((getClass() == o.getClass()) && (c == ((C) o).c) && (b == ((C) o).b) && (a == ((C) o).a)); } } public class EqualsTest3 { public static void main(String[] args) { A a1 = new A(1); B b1 = new B(1,1); C c1 = new C(1,1,1); System.out.println("a1.equals(b1) = " + a1.equals(b1)); System.out.println("a1.equals(c1) = " + a1.equals(c1)); System.out.println("b1.equals(a1) = " + b1.equals(a1)); System.out.println("b1.equals(c1) = " + b1.equals(c1)); System.out.println("c1.equals(a1) = " + c1.equals(a1)); System.out.println("c1.equals(b1) = " + c1.equals(b1)); System.out.println("a1.equals(a1) = " + a1.equals(a1)); System.out.println("b1.equals(b1) = " + b1.equals(b1)); System.out.println("c1.equals(c1) = " + c1.equals(c1)); } }