Re: destroy() method V.S. finalize() method

["David Morris" <David.Morris@xxxxxxxxxxxxx>]

Fred,

Do you know how the iSeries JVM handles soft references and their
impact on the garbage collection cycle? Does the iSeries JVM collect
them in LRU order or use some other algorithm? This document covers
most regular cases but doesn't describe soft references. It also
implies
that there is a phantom reference:

http://www.ibm.com/servers/eserver/iseries/perfmgmt/pdf/tuninggc.pdf

David Morris


>>> kulack@us.ibm.com 11/15/02 09:33AM >>>

On 11/14/2002 at 03:05:33 PM, java400-l-admin@midrange.com wrote:
An object gets destroyed (garbage collected) only when there is no
reference
to it.  When one stores an object into a Map, the Map has a reference
to
it.
To destroy this object one has to remove this entry from Map in
addition to
setting other references to null.
--- end of excerpt ---

Actually, from a Java language standpoint, thats not quite complete.
Objects may conceivably never be garbage collected.
The object gets destroyed when there is no reference to it AND the JVM
needs more
memory (because its currently out) and/or decides to garbage collect it
for
other reasons.

1) A close() or destroy() method is typical model for what you want to
do.
When the user calls close() or destroy(), take your action.
2) Also take your action in the finalize() method in case the user
leaks
the object
3) The weak reference would be a good mechanism to allow the garbage
collector
to claim your object (and you'd put some code in to detect it), but
you
still probably
want #1 and #2 in that case anyway.