Hello, For a few days I posted this on tomcat-user (no answers). I have "solved" the problem described below without exactly knowing why it worked. I believe this may be a bug in 4.0-release (compared to 4.0-B7) which is why I am submitting it on this list. Maybe one of the experts can have a look and decide what's the cause. The oracle JDBC driver wouldn't load in any of the 4.0-release classloaders, except maybe for the webappclassloader which I didn't try. The error was : java.lang.LinkageError: Class javax/sql/PooledConnection violates loader constraints at ctool.common.ConnectionCache.(ConnectionCache.java:93) I tried with or without -security, with -security to use a policy that allowed anything (verified with java.security.debug=all) but no improvement. With 4.0-B7 no problem occurred. This driver is delivered in a .zip file (classes12.zip). Somehow I got the idea to rename it into classes12.jar. Then the problem was gone. It is as if the new classloaders don't like files that are named .zip ISO .jar (even when the renamed .zip->.jar in fact still is a zip file). -- Peter Mutsaers | Dübendorf | UNIX - Live free or die [EMAIL PROTECTED] | Switzerland | Sent via FreeBSD 4.3-stable