Here are some things you can try.
a) Compare the console log (for starup) of your production server with a clean test version that has your app deployed. Compare the timestamps in the log.
b) What is in the server/xxx/data directory? Perhaps there are a lot of serialized sessions.
c) Use a tool such a jconsole or visualvm to monitor the heap usage, or set some of the JVM command line options to gather garbage collection statistics.
d) Use jmap or visualvm to get a heap dump and use visualvm to analyze it. If you do this for both the production and clean test versions you should be able to notice differences in object counts.