Re: Memory leak

From:
Daniel Pitts <newsgroup.spamfilter@virtualinfinity.net>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 25 Aug 2009 07:55:29 -0700
Message-ID:
<CXSkm.181187$3m2.13064@newsfe06.iad>
Ross wrote:

I appear to have some sort of a memory leak. Even though I can't see
where objects are being retained, the memory requirements of my
program seem way out of kilter with what is actually being stored. I
have one method which does 99% of the running, which has a single
array of size 400 of objects, none of which should be very large. But
I have to give the program tens of megabytes of heap space or it
crashes.

Giving tens of megabytes seems reasonable. Many of my programs require
256M+ of heap space to run properly.

I'm calling the System.gc(); method once per loop, just in case
garbage wasn't being collected, but as expected, no

Yeah, not likely to help, except to possibly cause a change in the delay
structure (if anything).

During each loop of the method, I copy the contents of the array into
another (locally declared) array, then swap the arrays. So, I could
have one copy of the array with out of date objects in it, but this
should be wiped next loop through.

Looking at the Runtime methods totalMemory() and freeMemory(), the
amount of memory in usage does go up and down, but eventually I burn
through 120m of head space - shouldn't happen.

Does it keep going up, or is that some sort of equilibrium?

Any hints as to what I could look for to see what is taking up so much
space?


Download a profiler and look at the heap dump, it will tell you what
objects are hanging around.

I use JProfiler, but it is a commercial product. Netbeans also has a
free profiler. There are well many other profilers.

Hope this helps.

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>

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