Java FAQ: Top Questions

CountDownLatch and CyclicBarrier in java.util.concurrent are synchronization aids for coordinating threads, but they serve different purposes.

• CountDownLatch:
  • Allows one or more threads to wait until a set of operations (count) completes.
  • Non-reusable; count cannot be reset.
  • Use case: Waiting for multiple tasks to finish.
• CyclicBarrier:
  • Allows a fixed number of threads to wait for each other at a barrier point.
  • Reusable; resets after all threads reach the barrier.
  • Use case: Iterative parallel algorithms.