Elevator pitch: It's a lightweight library for mapping arbitrary XML to your Java classes, mapped via annotations or external config, understands XML namespaces, can cache unmapped elements, preserves order of XML elements, it's extensible with custom converters, it's thread-safe and is lightweight at under 80kb with no external dependencies. Oh, and it has a permissive license: BSD.
More formally:
* Simple configuration. Object-to-XML mappings are configured via Java annotations or external XML configuration.
* Partial mapping. Map only a part of XML document that you are interested in. Unmapped XML will be preserved on output.
* XML namespaces are fully supported.
* Preserves order of XML elements from input to output.
* XML element and text mixing supported. Can map XHTML.
* Extensible. Custom converters can be written to support custom type conversions.
* Lightweight. Only 80kb in size with no dependencies.
* Thread-safe. Designed for multi-thread use.
* Permissive license: xmappr is released under BSD license.