This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
HashMap class is not thread-safe nad permits one null key,the HashTable class is thread-safe and permits non-null keys and values only. The Thread-safety that <i>HashTable</i> class provides has a performance penalty. HashTable class is a legay class that has been retrofitted to implement the Map interface.