Java Generics and Collections, 2nd Edition

Chapter 10. Queues

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A queue is a collection designed to hold elements for processing, yielding them up in the order in which they are to be processed. The corresponding Collections Framework interface Queue<E> has a number of different implementations embodying different rules about what this order should be. Many of the implementations use the rule that tasks are to be processed in the order in which they were submitted (First In First Out, or FIFO), but other rules are possible—for example, the Collections Framework includes queue classes whose processing order is based on task priority. The Queue interface was introduced in Java 5, motivated in part by the need for queues in the concurrency utilities included in that release. A glance at the hierarchy of implementations shown in Figure 10-1 shows that, in fact, nearly all the Queue implementations in the Collections Framework are in the package java.util.concurrent.

One classic ...