Debugging strange unmarshalling problems when using jaxb —02 September 2012
The other day I had a very strange unmarshalling issue with jaxb: unmarshalling (deserializing) from an XML file and then marshalling (serializing) the same object to another XML file resulted in different content. There were no errors thrown in the process and I had no idea as to why.
Finally I found a way to debug it on this page http://jaxb.java.net/guide/Unmarshalling_is_not_working__Help_.html
Unmarshaller u = ...; // this implementation is a part of the API and convenient for trouble-shooting, // as it prints out errors to System.out u.setEventHandler(new javax.xml.bind.helpers.DefaultValidationEventHandler()); u.unmarshal(new File("foo.xml"));
Based on the errors reported by the event handler it was straightforward to fix the problem (some property files that relax some validation rules were not on the classpath).