EvictingQueue: a non-blocking, bounded queue
In Guava 15, we are introducing EvictingQueue , which is a non-blocking, bounded queue that automatically evicts (removes) elements from the head of the queue when attempting to add elements to a full queue. This is different from conventional bounded queues, which either block or reject new elements when full.
Java provides several Queue implementations, depending on what features you need. For example:
Unbounded, non-blocking: ArrayDeque, LinkedList, PriorityQueue
Unbounded, blocking: LinkedBlockingDeque, LinkedBlockingQueue, SynchronousQueue
Bounded, blocking: ArrayBlockingQueue, LinkedBlockingDeque, LinkedBlockingQueue
However, a bounded, non-blocking implementation is noticeably missing from the JDK. Like many of the JDK implementations, EvictingQueue is not thread-safe and does not permit null elements. If you need thread safety, you must wrap it in a synchronized wrapper (Queues#synchronizedQueue). If you need null elements, please give this wiki page  a read.
An EvictingQueue can be used to keep track of recent items in a bounded buffer, or even as a simple FIFO cache. Hopefully you’ll find it useful!
-+Kurt Alfred Kluever, Guavian