Hunting Java memory. VSZ? 11.2 and 11.3

We are running into what appears to be a memory leak in java with a program that we are developing.

The growth has been confirm on a 12day test. When we look at garbage collection with hpjtune,  and jmeter, it appears to releasing the heap memory properly. 

Does anyone have a good answer to why VSZ is so different than the rate of growth for all of the other metrics?

Have you seen a java leak like this before?

Is this the way the OS allocates memory, where we are not actually leaking memory, as seen by jmeter?

Here are some metrics after 12 hours on the situation:

This is data from HP/UX 11.2:



Top start size: 262mb
Top End size: 278mb

Top res: 78mb
Top res end: 91mb

VSZ Start: 25968k
VSZ end: 42352k



procinfo pages start: 67561
procinfo pages stop: 71675



glance RSS start: 81.2mb
glance  RSS stop: 93.9mb





[LEFT]bash-3.2\# ./java -version[/LEFT]
[LEFT]java version "1.5.0.07-\_20\_mar_2007"[/LEFT]
[LEFT]Java\(TM\) 2 Runtime Environment, Standard Edition \(IBM build 1.5.0.07-\_20\_mar\_2007-05_31 20070511\)[/LEFT]
[LEFT]Java HotSpot\(TM\) 64-Bit Server VM \(build 1.5.0.07 jinteg:03.20.07-12:50 IA64W, mixed mode\)[/LEFT]
[LEFT]IBM Java ORB build orb50-20070501 \(SR5\)[/LEFT]
[LEFT]XML build XSLT4J Java 2.7.7[/LEFT]
[LEFT]XML build IBM JAXP 1.3.7[/LEFT]
[LEFT]XML build XML4J 4.4.9[/LEFT]

I don't use HP-UX so I am not sure about it. But on Linux I have seen virtual memory being consumed to nearly exhaustion at the OS level, but there was no apparent memory leak issue in the JVM. It was using JBoss AS.

As you use JVM 5.0+, I suggest you to use JConsole or similar tools to look at the memory space utilization in your JVM heap spaces and observe the dynamics of the spaces over time to look for possible signs of memory leak. Despite exhaustion of system memory, I did not observe noticeable heap growth and so I considered my installation a healthy one.