java.lang.LinkageError: loader constraint violation

[Ritu Bansal]

I am getting the following exception while trying to send an attachment email using Java mail API. The code runs locally using jetty server.

org.netbeans.modules.viewmodel.TreeModelNode@1f42ccb[Name=, displayName=e] NestedServletException org.springframework.web.util.NestedServletException: Handler processing failed; nested exception is java.lang.LinkageError: loader constraint violation: when resolving method "javax.mail.internet.MimeBodyPart.setDataHandler(Ljavax/activation/DataHandler;)V" the class loader (instance of org/mortbay/jetty/webapp/WebAppClassLoader) of the current class, org/springframework/mail/javamail/MimeMessageHelper, and the class loader (instance of org/codehaus/classworlds/RealmClassLoader) for resolved class, javax/mail/internet/MimeBodyPart, have different Class objects for the type javax/activation/DataHandler used in the signature

[Rob Spoor]

Sounds like an issue I'm still having with JBoss at work... Anyway, the problem is probably caused by two versions of the Java Activation Framework. Before Java 6 it was a separate library. A lot of frameworks and libraries still have it as a separate dependency. Try to see if removing activation.jar solves this issue.

(FYI, in my case it's the javax.xml.crypto package or a sub package that's causing the issue because it's a dependency of PicketLink. Red Hat is still working on the case.)