Hands-On High Performance with Spring 5

Concurrent collection classes

The concurrent collection classes provide more scalability and performance than other collection classes, such as HashMap or Hashtable. The following are useful concurrent classes provided in the java.util.concurrent package:

• ConcurrentHashMap: This is similar to HashMap and Hashtable, but it has been designed to work in concurrent programming without the need for explicit synchronization. Hashtable and ConcurrentHashMap are both thread-safe collections, but ConcurrentHashMap is more advanced than Hashtable. It does not lock the entire collection for synchronization, so it is very useful when there are a lot of updates and fewer concurrent reads.

• BlockingQueue: The producer-consumer pattern is the most common ...