[ http://issues.apache.org/jira/browse/DERBY-997?page=comments#action_12368394 ]
Daniel John Debrunner commented on DERBY-997: --------------------------------------------- Chris Newell wrote: (on derby-user) > I seem to have resolved my own issue as I was preparing a message to > this list seeking help (thanks!). Having spent more hours than I care to > admit trying to figure this out, and having seen another user in the > list archive that had a similar problem with no solution provided, I > thought that I'd post this with hopes of helping someone else that made > the same stupid mistake. [snip class cast exception ] > The solution was: > > ------------------------- > > I found that I had put a copy of derby.jar in both $TOMCAT/common/lib as > well as $TOMCAT/webapps/[my app]/WEB-INF/lib. I removed the one under > webapps and suddenly, as if by magic, I could count the rows in my > table.... And the world seems like a nicer place. > ClassCastException when executing queries with aggregates in app servers > ------------------------------------------------------------------------ > > Key: DERBY-997 > URL: http://issues.apache.org/jira/browse/DERBY-997 > Project: Derby > Type: Bug > Components: SQL > Reporter: Daniel John Debrunner > Assignee: Daniel John Debrunner > > Classes that implement the aggregates such as MAX/MIN are loaded as > user-defined classes due to old support for user-defined aggregates. > If the class loader setup running Derby is not well set up these classes are > loaded in a different class loader space to Derby's class leading to > non-comparable classes due to the the same class (dependend or subper-class, > not sure which) being loaded twice. > While this may be a user setup bug, it has occured frequently leading to > wasted time resolving the issue, it would be better if Derby ensured its > classes were loaded consistently. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
