Issue with JAXB unmarshaller

Hello,

We are currently experiencing an issue with the JAXB unmarshaller while unmarshalling an XML position message:

(JAXBElement<?>) SingletonFactory.getInstance().getCDFUnMarshaller().unmarshal(reader);

Two exceptions are thrown by it, a NullPointerException and a javax.xml.bind.UnmarshalException. The latter sometimes has a linked exception: org.xml.sax.SAXException: FWK005 parse may not be called while parsing. A pattern is not currently clear.

 Not all messages throw the exception, the failing messages are valid against the schema and, when the exception thrown is the javax.xml.bind.UnmarshalException, the unexpected element is not always the same.

 We would like to know whether there is a way to further troubleshoot the issue in order to correctly process the messages, especially regarding the "FWK005 parse may not be called while parsing" message.