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
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.)