Huge amount of JAR files in jboss/server/web/tmp/vfs-nested.tmp directory

Question

Sometimes we have huge amount of JAR files in jboss/server/web/tmp/vfs-nested.tmp directory.
For example today this directory contained over 350k jar files.
But on other hosts there are only 2 jar files in this directory.
What can be the root cause of this problem?

We use JBoss 5.1

UPDATE:
I found following information in release notes for JBoss 5.1.0.GA:

JBoss VFS provides a set of different switches to control it's internal behavior. JBoss AS sets jboss.vfs.forceCopy=true by default. To see all the provided VFS flags check out the code of the VFSUtils.java class.

So I do not understand what should I set?
Should I set -Djboss.vfs.forceNoCopy=true or -Djboss.vfs.forceCopy=false?
Or should I set both of them?

UPDATE 1:
I have read entire thread http://community.jboss.org/thread/2148?start=0&tstart=0 and now I am not shure that I should change either jboss.vfs.forceCopy or jboss.vfs.forceNoCopy.
According to this thread I will have OutOfMemory error instead of huge amount of files in tmp dir.

Answer 1

From here: http://sourceforge.net/project/shownotes.php?release_id=575410

"Excessive nestedjarNNN.tmp files in the tmp directory. The VFS unwraps nested jars by extracting the nested jar into a tmp file in the java tmp directory. This can result in a large number of files that fill up the tmp directory. You can disable this behavior by setting -Djboss.vfs.forceNoCopy=true on command line used to start jboss. This will be enabled by default in a future release, JBAS-4389."