There are a good number of articles that articulate functional differences between HashMap, Hashtable, and ConcurrentHashMap. This post compares the performance behavior of these data structures through practical examples. If you don’t have the patience to read the entire post, here is the bottom line: when you are confronted with the decision of whether to use HashMap, Hashtable, or ConcurrentHashMap, consider using ConcurrentHashMap since it’s thread-safe implementation without compromise in performance.
Performance Study
To study the performance characteristics, I have put together this sample program:
