XML-binary optimized package
23.12. XML-binary Optimized Packaging (Xop) RESTEasy supports Xop messages packaged as multipart/related. What does this mean? If you have a JAXB annotated POJO that also holds some binary content you may choose to send it in such a way where the binary does not need to be encoded in any way (neither base64 neither hex). This results in faster transport while still using the convenient POJO. More about Xop can be read here: http://www.w3.org/TR/xop10/.