I have set up Quartz.NET to run a scheduled job. It is amazing when I look at the thread IDs. They just get repeated in 10-thread interval.

I mean, for instance, if the first thread that gets to execute my job has ID 101 then the eleventh thread (that runs the same job at the eleventh interval) has the same ID, 101! 

It seems that Quartz.NET is using a pool of 10 threads, but more amazing is: Why do the threads have the same ID? Shouldn't they get new thread ID each time they are created?