Java hashtable Page

Java Hashtable

Java Hashtable is a legacy class in the Java Collections Framework that provides a hash table-based implementation of the Map interface. Hashtable is synchronized, making it thread-safe for use in multi-threaded environments. It offers constant-time performance for basic operations like put and get, making it suitable for scenarios where you need fast key-value pair retrieval. However, this synchronization comes with a performance overhead, making HashMap a preferred choice in single-threaded scenarios where synchronization is not required. Hashtable does not allow null keys or values, throwing a NullPointerException if attempted. Additionally, Hashtable is a legacy class, and its use is discouraged in favor of ConcurrentHashMap for concurrent scenarios or HashMap for single-threaded scenarios due to better performance. Overall, Hashtable provides a synchronized alternative to HashMap for scenarios requiring thread-safe operations on key-value pairs in Java applications.