You need to ENSURE that the xerces.jar file supplied with the JDOM download is in your classpath before any other XML classes, such as those that come with JAXP or Crimson. These other XML libraries, as well as older versions of Apache Xerces, support DOM Level 1 and SAX 1.0, not the required DOM Level 2 and SAX 2.0. The result is an exception being thrown. Check your classpath, and try again. If the classpath looks OK, the problematic JAR MIGHT also be HIDING in the system's standard extension directory.

You need to ensure that the xerces.jar file supplied with the JDOM download is in your classpath before any other XML classes, such as those that come with JAXP or Crimson. These other XML libraries, as well as older versions of Apache Xerces, support DOM Level 1 and SAX 1.0, not the required DOM Level 2 and SAX 2.0. The result is an exception being thrown. Check your classpath, and try again. If the classpath looks OK, the problematic JAR might also be hiding in the system's standard extension directory.