Please define a CountDownLatch in the context of Java?

You'll note that this question simply asks for a definition of a term used within the java programming language. You can only provide the definition or enhance your answer by describing how it is used and providing an example. Your choice of how to respond to this question will be based on your perception of the interviewer, the interview's progress, and whether you feel providing a more in-depth answer will better demonstrate your qualifications for the job.