Domino, DIIOP and JAVA - Bulk Recycler

Issue:
Developping a JAVA 1.6 program in charge of synchronizing an Oracle DB and a Lotus Notes DB using DIIOP protocol, I faced an unexpected error:

null
NotesException: Bulk recycler is not running
at lotus.domino.cso.RecycleThread.checkError(Unknown Source)
at lotus.domino.cso.Base.checkValid(Unknown Source)
at lotus.domino.cso.Database.validate(Unknown Source)
at lotus.domino.cso.Database.getDocumentByUNID(Unknown Source)

Reason :
The synchronization process was quite long (about 4 hours)
First section (2 hours) : Retrieve datas from Domino
Second section (2 hours) : Create Objects / Write to Oracle
Third section (30 minutes) : The Domino DB cleaning
During the "Next 2 hours" phase, the Domino connection was idle...
=> 2 hours of idle connection...TIMEOUT!!!

Solution1:
Modify the server properties:
1 - Open Domino Administrator
2 - Choose your server
3 - Click on Configuration tab
4 - Click on Internet Protocols tab
5 - Click on DIIOP tab
6 - Set the "Idle session timeout" to 0 minutes (infinite)

Solution2:
Modify the JAVA code closing the Domino DIIOP connection during the "second section (2 Hours)"
to avoid the timeout.