DelayQueue in Java: Usage Guide

DelayQueue is an unbounded blocking queue that implements the BlockingQueue interface and is used to store objects that implement the Delayed interface. The Delayed interface contains a getDelay() method that returns the object’s delay time. Objects can only be taken out of the queue when their delay time has been reached.

In a DelayQueue, objects are sorted based on their delay time when they are added to the queue, with the object having the shortest delay time being taken out first. The delay time of an object can be specified when creating it or adjusted dynamically.

The DelayQueue is commonly used for implementing scheduled tasks, such as in a task scheduler, where timed tasks are encapsulated as Delayed objects and placed in the DelayQueue. Then, a thread polls the DelayQueue and executes the corresponding task when the delay time is reached.