java.lang.LinkageError: loader constraint violation: when resolving method "javax.xml.soap.SOAPPart.setContent in JBoss FSW 6

Issue

• Everything deploys fine but when the web service is executed I get the error below:

java.lang.LinkageError: loader constraint violation: 
    when resolving method "javax.xml.soap.SOAPPart.setContent(Ljavax/xml/transform/Source;)V" 
    the class loader (instance of org/jboss/modules/ModuleClassLoader) of the current class, com/redhat/gss/Test, and 
    the class loader (instance of org/jboss/modules/ModuleClassLoader) for resolved class, javax/xml/soap/SOAPPart, 
    have different Class objects for the type setContent used in the signature

Note that this issue is known to occur only from code defined in a stack module (i.e. code found outside a deployment).