What is BlockingQueue? How can we implement Producer-Consumer problem using Blocking Queue?

java.util.concurrent.BlockingQueue is a Queue that supports operations that wait for the queue to become non-empty when retrieving and removing an element, and wait for space to become available in the queue when adding an element.

BlockingQueue doesn’t accept null values and throw NullPointerException if you try to store null value in the queue.

BlockingQueue implementations are thread-safe. All queuing methods are atomic in nature and use internal locks or other forms of concurrency control.

BlockingQueue interface is part of java collections framework and it’s primarily used for implementing producer consumer problem.
Check this post for producer-consumer problem implementation using BlockingQueue.