We have an applicatons that we developed on tomcat and have recently moved over to Sun Java Web Server 6.1. In order to configure our Session we are using a connection pool provided by C3p0(have tried DBCP with similar results) and are using a servlet filter to manage a session from the SessionFactory for each sevlet request. After moving to Sun Java Web Server 6.1 during stress testing we have started seeing the following error...

javax.servlet.ServletException
at com.graysail.access.hibernate.servlet.HibernateSessionManagerFilter.doFilter(HibernateSessionManagerFilter.java:55)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:280)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:509)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:212)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:509)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:209)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:509)
at com.iplanet.ias.web.connector.nsapi.NSAPIProcessor.process(NSAPIProcessor.java:161)
at com.iplanet.ias.web.WebContainer.service(WebContainer.java:586)
----- Root Cause -----
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:762)
at java.util.HashMap$KeyIterator.next(HashMap.java:798)
at net.sf.hibernate.impl.BatcherImpl.closeStatements(BatcherImpl.java:170)
at net.sf.hibernate.impl.SessionImpl.disconnect(SessionImpl.java:3306)
at net.sf.hibernate.impl.SessionImpl.close(SessionImpl.java:552)
at com.graysail.access.hibernate.HibernateServletSessionProvider.clearSession(HibernateServletSessionProvider.java:49)
at com.graysail.access.hibernate.HibernateServletSessionProvider.commitAndClearSession(HibernateServletSessionProvider.java:58)
at com.graysail.access.hibernate.servlet.HibernateSessionManagerFilter.doFilter(HibernateSessionManagerFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:280)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:509)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:212)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:509)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:209)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:509)
at com.iplanet.ias.web.connector.nsapi.NSAPIProcessor.process(NSAPIProcessor.java:161)
at com.iplanet.ias.web.WebContainer.service(WebContainer.java:586)

I am stumped and not really sure what is going on...It would suggest that two threads are using the same session but I am not really sure how that would happen. Any help is greatly appreciated...

Thanks,
Scott

Oh yeah...

Hibernate 2.1.2
Using oracle 9

I will get a debug level trace tomorrow when I get back to work...

Thanks,
Scott

certainly looks like two concurrent threads both get the same session.

check your session-handling code