Hi, i think i have the same error but still can't solve it. I'm using netbeans 5.5 and Sun Java System Application Server Platform Edition 9.0_01 (build b14). This is a test web application which uses persistence. This is what i've got so far:
First i got this error:
[i]javax.servlet.ServletException: Error in allocating a connection. Cause: Class name is wrong or classpath is not set for : org.postgresql.ds.PGSimpleDataSource[/i]
I changed the class name on the Connection Pool on the Application Server to org.postgresql.Driver which is the class i use on netbeans to connect to the database (i think netbeans should do this).
Then restarted the application server and got this:
[i]javax.servlet.ServletException:
Exception Description: Attempted to deploy PersistenceUnit [testPU] for which predeploy method either had not called or had failed
root cause
Exception [TOPLINK-28013] (Oracle TopLink Essentials - 2006.8 (Build 060830)): oracle.toplink.essentials.exceptions.EntityManagerSetupException
Exception Description: Attempted to deploy PersistenceUnit [testPU] for which predeploy method either had not called or had failed[/i]
I would like to know where did you place your driver for this to work. Thanks
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