How do you find a memory leak in Java (using for example JHat)? I have tried to load the heap dump up in JHat to take a basic look. However I do not understand how I am supposed to be able to find the root reference (ref) or whatever it is called. Basically I can tell that there are several hundred meg of hash table entries ([java.util.H...
How come every object appears to be marked new, instead of just objects that are in the second snapshot but not in my baseline snapshot? Looking around online, I see some suggestions that I need to use hprof instead of jmap to make my memory dumps, but it appears that hprof generates dumps in exactly the same format. This is JDK 1.6.0_...
I am trying out a tool jhat here to test my java memory usage. It reads in a heap dump file and prints out information as html. However, the tables shows as follows: Class Instance Count Total Size class [B 36585 49323821 class [Lcom.sun.mail.imap.IMAPMessage; 790 16254336 class [C 124512 12832896 class [I 23080 11923504 ...
Does anyone know the OQL syntax for finding new objects only in a heap output? I can't find good documentation on OQL options, sun even has an example of new-only output without sample syntax of the query that generated it.What I've done is Created a set of heaps with jhat Served them up with jmap -baseline, which marks objects not in ...
I have a 6.5GB Hprof file that was dumped by a 64-bit JVM using the -XX:-HeapDumpOnOutOfMemoryError option. I have it sitting on a 16GB 64-bit machine, and am trying to get it into jhat, but it keeps running out of memory. I have tried passing in jvm args for minimum settings, but it rejects any minimum, and seems to run out of memory be...
I am running the JHAT memory profiler. This example shows information attached to a single object: https://hat.dev.java.net/doc/examples/object.html This info includes a section "object allocated from". When I run jhat, I get everything except the "object allocated from" section. Why? I can't see any setting that controls this. Enviro...
Hi All, I'm trying to use jhat/OQL to trace a memory leak in our Tomcat container. The question I want to ask is: "Show me all the instances (and sub-instances) of foo.bar.Cacheable class that are reachable from javax.servlet.http.HttpSession" I managed to come up with the following, but this doesn't show subclasses of foo.bar.Cacheab...