I\'ve been using com.sun.xml.bind.marshaller.NamespacePrefixMapper in my project, and i had no problem with it in JDK 6u17. Now I just updated to 6u18, and I sa
com.sun.xml.bind.marshaller.NamespacePrefixMapper
The below post at stack overflow answers the question: Define Spring JAXB namespaces without using NamespacePrefixMapper
Key is to include the rt.jar at build time and remove it from the application after compilation.