HashMap vs Hashtable: Key Use Cases

HashMap and Hashtable are both data structures used to store key-value pairs, but they have some differences.

HashMap is suitable for multi-threaded environments due to its asynchronous nature, which does not ensure thread safety. Therefore, using HashMap in a single-threaded environment may lead to better performance. Additionally, HashMap allows null as both key and value, whereas Hashtable does not.

Hashtable is thread-safe and suitable for read and write operations in a multi-threaded environment. It uses synchronisation internally, providing better support for concurrent operations. However, the performance of Hashtable may be impacted due to the presence of synchronisation.

Therefore, depending on specific requirements and environment, one can choose to use HashMap or Hashtable. For instance, in a single-threaded environment where data operations do not require thread safety, one can choose to use HashMap; whereas in a multi-threaded environment where thread safety is needed, one can choose to use Hashtable.