Скачать или смотреть Java Collections Blocking Queue Part 7

Blocking Queue is an extension of the Queue interface in Java. BlockingQueue provides additional methods for blocking access of the queue. BlockingQueue has 4 different set of methods available in order to add or remove elements from the queue.

BlockingQueue has following implementations.
ArrayBlockingQueue
LinkedBlockingQueue
PriorityBlockingQueue
SynchronousQueue
DelayQueue

Queues can be classified as unbounded or bounded queues.
Unbounded queues have no capacity or size defined and can grow as long as memory is available.If the jvm runs out of memory, outofmemory error will be thrown.
Bounded queues have the the capacity defined and cannot grow beyond the specified size. If you try to add an item to full queue, the queue will return null or false. However, blocking queue has some additional methods available which can block access to queue. These two methods are put and take. If you tried to add an item to a full blocking queue, the thread will wait until spaces becomes available. Similarly, if you try to remove an item from an empty blocking queue, the thread will wait until some other thread add value into the queue. Blocking quues are thread-safe and should be used where data integrity is important.

Blocking queues can be used to implement producer consumer model. In this model, producer produces items and consumers consumes them. When the queue is full, the producer waits to add items to queue. Similarly consumer waits if the queue is empty.