Thank you Felipe.
I have almost the same code as you as I followed the sample in the documentation here : http://help.sap.com/saphelp_nwpi711/helpdata/en/48/64db09c88307dbe10000000a42189b/content.htm?frameset=/en/48/7237c336701b5ae10000000a42189c/frameset.htm¤t_toc=/en/b4/3f9e64bff38c4f9a19635f57eb4248/plain.htm&node_id=527
But it's ok now. I successfully called my JCO Server from the abap side
Do you have any idea for the other questions :
Now, I know how to call a function module that calls my Java JCO Server but do I have to register every FM in my java code that calls my Java JCO Server ?
Is this line mandatory for every FM that calls the server ?
factory.registerHandler("Z_TESTRFC_LEBR2", customConnectionHandler);
Regards