title: EJB Timer usage recommendations
body: <p>I want to schedule a job, which read some entities, call some ws and write/update some entities. This job should be processed after the moon, for example at 01am. I have 2 problems about this issue. First is that Scheduler takes constant parameters, my requeirement is that Scheduler should be adjustable via some ui. Is there a suitable way to do this? Otherwise I have to adjust the scheduler for example every 30 min, and inside the method I have to look some variable time values whether they are met or not. The second problem is inside the Scheduler method usertransaction is started, and when I call the method, which calls the utx.start, I get "thread is already associated with a transaction!" exp. What shall I do? Recommendation pls.  Thanks in advance.</p>