Web AS restarts due to classes being loaded multiple number of times

Question

Hi,
We are developing a custom application which uses Dynpro for UI and EJBs/java for business and DAO layer.
->The application size is very big and to make the build and deployment faster, we have split the application into multiple ears.
->We have made sure that none of the classes are repeated across ears.
->We are using Web AS 2004s SP12 on Solaris UNIX platform.
With all the ears being deployed on the application server, we notice application server being restarted once/twice per day. We have gone through the logs etc in detail and we found that most of the application classes are being loaded multiple number of times. In some cases, same class is being loaded more than 150 times. Due to this reason, permSpace area of JVM is getting exhausted and JVM is crashing. permSpace of JVM is set to 1024M at the moment.
Any thoughts on what could be wrong here?
Please let me know if you need any more details on this.
Thanks, Chandra

Answer 1

Hi,
Which JDK version is in use ?  If possible, use JDK 1.4.2.17
Change Perm size :   -XX:PermSize=512m -XX:MaxPermSize=512m
Check if the below mentioned JVM parameters exists in the list :
-verbose:gc
-Xloggc:GC.log
//   -Xmx2048m (if -Xmx mentioned the JVM Parameter list, remove it) as you have already mentioned in the JVM Heapsize  //
-Xms2048m
-XX:PermSize=512m -XX:MaxPermSize=512m
-XX:NewSize=320m -XX:MaxNewSize=320m
-XX:SurvivorRatio=2
-XX:TargetSurvivorRatio=90
-XX:+PrintGCDetails
-XX:+PrintGCTimeStamps
-XX:+UseParNewGC
-XX:+HandlePromotionFailure
-XX:+PrintClassHistogram
Regards
Shaji