Implements Comparable

Question

I am trying to create a holder object, which holds two values. It is called TwoTuple. I implemented Comparable so that I can use it in a Set.
public class TwoTuple<A,B> implements  Comparable<TwoTuple>{
     public final String first;
     public final B second;
     public TwoTuple(String first, B b){
          this.first = first;
          second = b;
     public int compareTo(TwoTuple tt){
                 int result = first.compareTo(tt.first);
                 return result;
     public String toString(){
          return "Variable == " + first + "  Value == " + second;
}This is my test class:
public class Test{
     private static Set<TwoTuple> state = new HashSet<TwoTuple>();
     public static void main(String[] args){
          state.add(new TwoTuple<String,Boolean>("Testing", true));
          state.add(new TwoTuple<String,Boolean>("Testing", true));
          state.add(new TwoTuple<String,Boolean>("Testing", true));
          for(TwoTuple tt : state)
               System.out.println(tt);
}Output:
Variable == Testing  Value == true
Variable == Testing  Value == true
Variable == Testing  Value == trueWhy am I still getting 3 of the same elements in this Set?

Answer 1

This doesn't address the hash code issue, but here's an implementation of equals() for a similar class I have called Pair. It's generic & takes two objects F & S (first & second). Might apply to what you're doing, or may not.
@Override public boolean equals(final Object object) {
     if (this == object) {
          return true;
     if (object == null) {
          return false;
     if (getClass() != object.getClass()) {
          return false;
     @SuppressWarnings("unchecked")
     final Pair<F,S> other = (Pair<F,S>)object;
     if (first == null) {
          if (other.first != null) {
               return false;
     } else if (!first.equals(other.first)) {
          return false;
     if (second == null) {
          if (other.second != null) {
               return false;
     } else if (!second.equals(other.second)) {
          return false;
     return true;
}