I have bounded my problem. The problem is, that when i persist the Timer during shutdown, i'm not able to identify the Timer at startup.
At startup i check all Timers of the TimerService (timerService.getTimers()), but i don't get any timer, so i create a new timer with my ID. When JBoss is finished with startup, a second Timer (the old one, which was persist before) will start too. After next restart i have three timer, and so on...
How can i check, that the timer with my ID is already created or rather is loaded again?
Thanks for Help.