Hi Sergiu, I happen to use Tomcat 6.0.18 as the servlet container and JDK 1.6. But I also chanced upon this article while digging for more info: http://blog.spaceprogram.com/2007/05/how-to-fix-linkageerror-when-using-jaxb .html http://java.sun.com/j2se/1.5.0/docs/guide/standards/ I am trying to fix this using the endorsed library mechanism. It seems only JDK 1.6 would have the java.lang.LinkageError and not JDK 1.5. Will keep you posted once this is done. Thanks Sergiu...