Difference between Dictionary and Hash Table

Dictionary

• 1.    Request to access for non-existing key will throw an exception.
• 2.    Dictionary is a Generic Type.
• 3.    Generic Collections are a lot faster for value types as there is no boxing and Unboxing.
• 4.    Dictionary Public static members are thread safe, but any instance members are not guaranteed to be thread safe.
• 5.    Dictionary is preferred over Hash Table.

Hash Table

• 1.    Request to access for non-existing key gives null instead of error.
• 2.    Hash Table is Non-Generic Type.
• 3.    Hash Table also have to Box/Unbox, which may have memory consumption as well as performance penalties.
• 4.    Hash Table is a thread safe for use by multiple reader threads and a single writing thread.