OnJava8-Examples/operators/EqualsMethod.java

// operators/EqualsMethod.java
// (c)2021 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// Default equals() does not compare contents

class ValA {
  int i;
}

class ValB {
  int i;
  // Works for this example, not a complete equals():
  public boolean equals(Object o) {
    ValB rval = (ValB)o;  // Cast o to be a ValB
    return i == rval.i;
  }
}

public class EqualsMethod {
  public static void main(String[] args) {
    ValA va1 = new ValA();
    ValA va2 = new ValA();
    va1.i = va2.i = 100;
    System.out.println(va1.equals(va2));
    ValB vb1 = new ValB();
    ValB vb2 = new ValB();
    vb1.i = vb2.i = 100;
    System.out.println(vb1.equals(vb2));
  }
}
/* Output:
false
true
*/