ConcurrentHashMap in Java is introduced as an alternative of Hashtable in Java 1.5 as part of Java concurrency package. Prior to Java 1.5 if you need a Map implementation, which can be safely used in a concurrent and multi-threaded Java program, then, you only have Hashtable or synchronized Map because HashMap is not thread-safe. With ConcurrentHashMap, now you have a better choice; because not only it can be safely used in the concurrent multi-threaded environment but also provides better performance over Hashtable and synchronizedMap. ConcurrentHashMap performs better than earlier two because it only locks a portion of Map, instead of whole Map, which is the case with Hashtable and synchronized Map. CHM allows concurred read operations and the same time maintains integrity by synchronizing write operations. We have seen basics of ConcurrentHashMap on Top 5 Java Concurrent Collections from JDK 5 and 6 and in this Java tutorial, we will learn:
Ø How ConcurrentHashMap works in Java or how it is implemented in Java.
Ø When to use ConcurrentHashMap in Java
Ø ConcurrentHashMap examples in Java
Ø And some important properties of CHM.