Auto-deploying and memory leaks

[bmelloni]

I have noticed that when I use auto-deploy in development, and redeploy many times, I eventually get out-of-memory errors. Several other people that I know, working on different applications have the same problem.

This does not seem to happen when deploying only once.

Is this a well known bug?

Is this a well know bug with log4j, struts, hibernate or tiles?

Or, if this is a problem with my application (and the applications of those other people), what is the likely cause? Since it happens to so many people independently developing separate applications, I assume it is a well-know and easy to commit error.

Thanks for any insight.

[starksm64]

There have been issues with several different components hanging on the class loaders across deployments which causes leaks. Create a jira issues if you have a reproducible deployment leak.

[dissonance]

Sometimes, the result of the OutOfMemory error (I assume this is in the PermGen space since I've encountered this error myself) is because of the JavaBeans Introspector's cache not being garbage collected on redeployments. I found this out indirectly looking at

http://www.springframework.org/docs/api/org/springframework/web/util/IntrospectorCleanupListener.html

Here's an excerpt from the java.beans.Introspector javadocs:

"Because the Introspector caches BeanInfo classes for better performance, take care if you use it in an application that uses multiple class loaders. In general, when you destroy a ClassLoader that has been used to introspect classes, you should use the Introspector.flushCaches or Introspector.flushFromCaches method to flush all of the introspected classes out of the cache"

If you don't use Spring, just implement the ServletContextListener and in your contextDestroyed method, be sure to call Introspector.flushCaches, then plug your listener in web.xml

From JBoss' side, you can also try looking at the Wiki:

http://wiki.jboss.org/wiki/Wiki.jsp?page=OutOfMemoryExceptionWhenRedeploying

Cheers
-j yi

[dissonance]

I need to read the dates of these posts before replying : p