Can anyone tell me what the differences are between smack, tinder and whack?
Are tinder and whack slim-down versions of smack? Do the 3 libraries serve different purposes?
Smack is a client library. You can use it to log into an XMPP domain and make use of the functionality it provides. Typically, Smack is used to implement a instant messaging client.
Tinder is a low-level XMPP library. It provides Java implementations of basic XMPP entities, such as Stanzas (called 'Packet' in XMPP), JIDs and Components (which typically implement part of the functionality of an XMPP server). Although in theory, Tinder could be used to implement client functionality, it currently is primarily used on the server-side. Both Whack and Openfire (an XMPP server implementation) use Tinder-defined entities. Smack does not use Tinder at all.
Whack is Java library that is used to implement external components. Whack allows a Component (as defined in Tinder) to run as a stand-alone process. Whack allows you to connect this process to an XMPP domain. This way, you can extend the functionality provided by that domain without modifying the implementation of the server software.