CODEWITHSUNDEEP
javatomcatprofilingclassloader
Sun
Sun

Reputation: 53

Too many classes loaded when application is deployed on tomcat

We are having a web application which depends on around 125 jars including spring, hibernet, zk, etc.

When we start the tomcat server, it loads around 55K classes into the permgen. Coz of this huge class loading, application startup takes significant amount of time. Moreover permgen space required by application is very high as other classes are also loaded during the program execution.

I had tried with -XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled options specified for java. But only 42 classes were unloaded after sometime.

Any help or pointers are highly appreciated.

Upvotes: 3

Views: 2007

Answers (2)

mana
mana

Reputation: 6547

The jars are in the classpath for a reason. They are probably added to you webapp through a build management system (maven, gradle, ...) - therefore there may be some dependencies to these jars.

Removing jars from the classpath will produce NoClassDefFoundError. I guess you have to live with that amount of jars unless some of them are not needed (which is not easy to find out).

Best check you dependency graph (maven and gradle have them) for possibly redundant, not needed or obsolete jars in your project. Also check for jars that come in different version like random-1.0.0.jar and random-1.0.1.jar and exclude one of them if possible.

Upvotes: 1

James Black
James Black

Reputation: 41858

You may want to use a tool to remove unneeded classes.

This question dealt with this very issue:

Tool to remove unnecessary dependencies in a Java project

But this question on Oracle may be more useful:

https://forums.oracle.com/forums/thread.jspa?threadID=1311910

I think that GenJar2 (http://code.google.com/p/genjar2/) may best meet your needs though.

Upvotes: 0

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