title: JBOSS server throwing exception -cannot be cast to org.apache.xml.dtm.DTMManager
body: <p>We are migrating Weblogic 12C server to JBOSS 7 and while testing the application, the following exception occured:</p>
  
  <blockquote>
    <p>Exception occured during xpath Evalution : java.lang.ClassCastException: org.apache.xml.dtm.ref.DTMManagerDefault cannot be cast to org.apache.xml.dtm.DTMManager</p>
  </blockquote>
  
  <p>We have Xalan.jar (2.6.0)packaged in war file under web-inf folder. It seems the JBOSS server does not have a module set for xalan jar so it should be present only through our .war file.</p>
  
  <p>Could you please explain to me why this exception occurred?</p>