Re: Strange things with java...
Roberto Nicastro wrote On 05/11/07 13:51,:
Hi all,
i have this piece of code
Suppose that lstA is List of 3 Objects
List<Object> lstA = ...something;
List<Object> lstB = lstA;
...
[block A] //this is a block of code
...
Inside block A i remove one item from lstA, so lstA become a List of 2
Objects. Inside block A i never touch lstB.
Why at the end of block A also lstB is with 2 elements? How is this
possible?
An analogy (I love analogies!) that may help you
understand what others have pointed out: lstA is the
number on the debit card in your wallet, and lstB is
the same string of digits recorded in your password-
protected on-line form-filler assistant. In [block A]
you hand the card to a local merchant to pay for your
new jPea, 150 silver splonders including VAT. Then
you go to your computer, use the automatic form-filler
to log in to your bank account, and check the balance.
Are the 150 silver splonders still there to be spent?
One bank account, two copies of the account number.
One List instance, two references to it. Spend money
with the debit card, and the balance change is visible
when you use the copied number. Change the List via
listA, and the change is visible through listB.
--
Eric.Sosman@sun.com