https://jira.jboss.org/browse/JBWS-2671
From that (Closed and not fixed) defect, looks like it is an issue with Java 1.6. I've run into the same problem and I'm looking for some solution that wont have me changing my code since I've been developing with 1.6 API's for some time now. Maybe the solution is to use a different API, such as Apache.