This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
core pool size - size of the thread pool(no.of worker threads working in parallel) in normal situation
max pool size - pool size can go up to this point if thread pool is busy(means all workers are busy and more jobs are there waiting and in this situation, new workers will be created); but it always attempts to stay at core size whenever idle threads present
queue size - is the no.of jobs waiting to be processed by the worker threads; when the queue is full and all worker threads are busy, no additional jobs can be submitted to the pool
worker threads - threads that are waiting for the jobs; they keep executing the available jobs in the queue, and when there are no more jobs to be done, they sit idle, but jump to work at the first sight of any new job