Babbler is a young XMPP client library for Java 8 SE built on top of JAXB, which allows you to write XMPP clients as well as external server components using the XEP-0114: Jabber Component Protocol.
JAXB as underlying technology makes it robust and allows you to write extensions in a simple and clean manner.
It aims to provide good (JavaDoc) documentation, clean code, an easy to use API and a high level of software quality (which is currently ensured by more than 800 unit tests).
Note: Since this project is quite young, it is still a work in progress and the API might change. Comments on the API are highly appreciated (write a message on my BitBucket account or comment on my Blog).
On this site you learn about some general design considerations, a brief user guide and API documentation.