Re: finalize() overhead

From:
Eric Sosman <esosman@ieee-dot-org.invalid>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 07 Nov 2007 21:38:40 -0500
Message-ID:
<BbadnbWcTKcp66_anZ2dnUVZ_v6rnZ2d@comcast.com>
Joe Seigh wrote:

I guess overriding finalize() isn't recommended too much because
of it's adverse effect on GC performance. But I assume that
if it's used a lot. You need finalize() for things like guaranteeing
proper clean up of non-memory resources like file descriptors and
db connections. One way anyway.

So this sort of use of finalize is considered acceptable? Or should
it be avoided at all costs even if you leak file descriptors or
whatnot?


     Can't remember who said it (Bloch? Eckel? not sure), but
the thing to keep in mind is that finalize() is a creature of
the garbage collector, the garbage collector's concern is
memory and memory only, so finalize() should be about memory
and memory only. Eckel (I'm sure, this time) also suggests
a debugging role: If an object becomes garbage without its
close() or dispose() or disconnect() method being called, a
finalize() can emit a warning message to that effect.

     If you need to get rid of file handles, database connections,
windows, sessions, sockets, locks on the frammis interface, or
other non-memory kinds of things, you should provide a close()
or dispose() or terminate() or ahhScrewItAll() method to shut
down, release, relinquish, or otherwise sever your association
with such entities. The finalize() method is *not* the right
vehicle for such things; finalize() is *not* a "destructor."

--
Eric Sosman
esosman@ieee-dot-org.invalid

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