equals() method - comparing Objects

[Kevin Nielsen]

Hi guys,

I'm studying for the SCJP 1.5 exam by reading the K&B book and some additional stuff (Sun's JDK 1.5 tutorials + other things).

I'm a bit confused over a statement in the K&B book - page 389 - "Wrappers won't pass equals() if they're in different classes"

...does this also means (like the == operator), that my own objects will fail the test or does this only apply to Wrappers?

Can somebody help on this?

regards,
Kewin

[Joyce Lee]

Hi Kewin,

"Wrappers won't pass equals() if they're in different classes"

This statement is explained with a code example on page 384 of K&B.

Here is another example:

Integer a = new Integer(2);
 
Long b = new Long(2);
System.out.println(a.equals(b)); // false because of different classes
 
Integer c = new Integer(2);
System.out.println(a.equals(c)); // true because of same classes and value

Joyce
[ July 27, 2005: Message edited by: Joyce Lee ]