title: What is the meaning of "Thread Group" in JMeter?
body: <p>I don't clearly understand what is the meaning of a "Thread group" in JMeter. Does that means all the tests (Java requests etc) belong to a certain thread group run in a one thread or each  test in that thread group runs in a separate thread? I couldn't get a clear understanding about this from JMeter documentations or googling.</p>