ConcurrentHashMap JDK1.8

ConcurrentHashMap is a concurrent version of HashMap introduced in Java 1.5 and improved in Java 1.8. It is designed to support high-level concurrency and provides thread-safe operations for concurrent access.

In JDK 1.8, ConcurrentHashMap was enhanced with several new methods and performance improvements. One notable improvement is the introduction of lock striping, which divides the map into separate segments, each with its own lock. This allows multiple threads to update different segments concurrently, reducing contention and improving performance.

Another improvement in JDK 1.8 is the addition of the forEach method, which allows you to perform an action on each key-value pair in the map in parallel. This can be beneficial when you have a large number of entries to process concurrently.

Furthermore, JDK 1.8 introduced the computeIfAbsent and computeIfPresent methods, which allow you to atomically compute values based on keys. These methods provide a convenient way to update the map's values in a thread-safe manner.

In summary, ConcurrentHashMap in JDK 1.8 provides better performance and enhanced functionality for concurrent access compared to its earlier versions.