HashCodes and Reference Variables

[Sudhanshu Mishra]

Hi all,
I tried to print the value of a reference variable of a class(equals and hashcode not overriden) and i get a value like Classname@hexnumber.
I found out that the hex-number is nothing but the memory address of the object.
BUT,when i override the hashcode and equals,and then i create two equivalent objects,and print the reference variables,I get the same values,because they had same hashCodes,but when i tried to compare them using ==,they were not equal.
So,my question is,even if the reference variables show equal values when printed,why are they not '=='.Do the reference variables store somethong else and display something else?

here is a code

class HasHash {
  public int x;
  HasHash(int xVal) { x = xVal; }
  public boolean equals(Object o) {
    HasHash h = (HasHash) o; // Don't try at home without 
                             // instanceof test
    if (h.x == this.x) {
      return true;
    } else {
      return false;
    }
	}
  public int hashCode() { return (x * 17); }
}

class UseHash
{
	public static void main(String...a)
	{
		HasHash h=new HasHash(1);
		HasHash h1=new HasHash(1);
		System.out.println(h+"  "+h1);
		System.out.println(h.hashCode()+" "+h1.hashCode());
		if(h1.equals(h1))System.out.println("h.equals(h1)");
		if(h1==h)System.out.println("h1==h");
		else System.out.println("Nopes!the bit patterns in ref. var. are something different");
	}
}

BIG CONFUSION.PLEASE HELP ASAP.

Thanks...

[Lanny Gilbert]

Comparing h and h1 using "==" means that h and h1 are referring to the same exact object in memory, which they aren't
However, h.equals(h1) *should* be true at this point, but h==h1 is not.

[Sudhanshu Mishra]

Hi ,
Yes,I know they don't refer to the same object but why then they give the same value when they are printed?

[Matthew Brown]

When you print out the values, what's actually happening is that toString() is being used to convert to a String. You haven't overridden toString(), so it's using the version defined in Object.

And if you look up that definition in the Javadocs, you see:

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

getClass().getName() + '@' + Integer.toHexString(hashCode())

Which means that if you've overridden hashCode() to return the same values, then the output will be the same, even if they aren't the same object.