I know you can do it because I applied patches to Inline::Java to allow that. Problem is I have never tried since I don't know Tomcat that well.

To start I think you have to load InlineJavaServer.jar and instantiate InlineJavaServer in a separate thread. That will create listening server that the Perl code should then be able to connect to using SHARED_JVM=1 and START_JVM=0.