Hi,

I have a class Obj. I created three objects o1,o2,03. Objects are equal if their id is equal. For example, o1 and o3 are equal. I tried adding these three objects to a HashSet, and when I print the size of the hashset I get "3" and not "2". Something is not right with the equals or hashcode method. Can someone shed some light?

code snippet:

import java.util.*;

public class Test
{
public static void main (String[] args)
{
 Set hs = new HashSet();
 Obj o1 = new Obj ("w", 10);
 Obj o2 = new Obj ("r", 20);
 Obj o3 = new Obj ("w", 30);
 
 hs.add(o1);
 hs.add(o2);
 hs.add(o3);
 
 System.out.println(hs.size());
}

public static class Obj
{
 String id;
 int length;
 
 Obj (String id, int length)
 {
  this.id = id;
  this.length = length;
 }
 
 boolean equals (Obj o)
 {
 
  if (o == null)
   return false;
  else if (o instanceof Obj)
   return (this.id.equals(o.id));
  else return false;
 }
 
 public int hashCode()
 {
  return id.hashCode();
 }
}
}