Number class problem

[Saurabh Khanna]

Hi Folks

Both wrapper classes Long and Integer extend Number class.

If i use the following code:

 
Long l = new Long (4);
Integer i = new Integer(4);
 
if(l.equals(i)) 
  System.out.println("equal");
else 
  System.out.println("unequal");

Why does it print unequal even though the value inside both the objects is really equal (that is 4) ???

Thanks in advance.

regards
Saurabh

[Ernest Friedman-Hill]

Because they're two different classes, and that's how their equals() methods are implemented. Would you want a JButton labelled "OK" and a JRadioButton labelled "OK" to compare equal?

[Saurabh Khanna]

Hi Ernest

Hmmm, that makes sense. I would'nt want JButton and JRadioButton to compare equal. However, one would expect the wrapper classes to exhibit same sort of behaviour as the primitives, well thats obviously not the case as you explained above.

For example, the following code prints equals:

  
    long l = 4;
    int i = 4;
 
    if(i == l)
      System.out.println("equals");
    else
      System.out.println("not equals");    

How can i get the above effect using wrapper classes?

regards
Saurabh

[Ernest Friedman-Hill]

You could call longValue() on each Number, and compare those values using "==".