Java and JavaScript in the Database

Hello.

I have been asked to find a way to solve this situation (I have not developed the java code and I have no work experience at coding with java):

- A PL/SQL stored function is called using JDBC from a web application.
- When the execution of the stored function ends, the java class closes the connection (at least, I can see in a log that con.close() is called, con being a Connection) but the usage of memory in the db does not decrease, so that the usage of memory becomes huge sooner than later.
- When I call the stored function from sqlplus the memory usage in the db decreases when I end my session.

Is there an easy way of ending the session from java in order to avoid this situation?

Thanks in advance.