Java 6 JAXB/JAXP/SAAJ reference implemetation conflict with Xerces

Can there be conflict between the JAXB/JAXP/SAAJ reference implementation in Java 6 and Xerces 2.x referenced by a WAR in a standard Java EE container like Tomcat and if so how given the classes have the same name, but are i开发者_开发问答n different namespaces?

I had a problem with JAXP/SAAJ and Tomcat. I think I had to put the SAAJ jar in the Tomcat endorsed directory to override the existing one, due to a conflict with another class which had the same package and class name