Via Xing I discovered a meeting of the Java User Group Karlsruhe which took place yesterday at the Universität Karlsruhe. The JUG-KA is quite young actually - it was just the second meeting held ever. As it's just a 10 minute drive I decided to attend it (and it was quite a strange feeling to sit in a lecture room at my old University ;-)
There were about 50 people attending and the first presentation was an overview of the Spring Framework held by Oliver Schlicht from Synyx. The second presentation was done by Dr. Stefan Schneider from SUN and was about Java Hotspot VM garbage collection and memory pool sizing techniques, including demos with visualgc and JCconsole. The bottom line was that with Java 6 the VM settings are good enough most of the time and the only thing left to configure is the maximum heap size. Nevertheless it's a good idea for every developer to have a look a the memory usage of an application with the mentioned tools.
The next meeting is scheduled for sometime in October (IIRC one topic will be again Spring), but I think it would be nice to also have a more informal Stammtisch.