When using JDK 6 (up to JDK 6 Update 3) to run ActiveMQ you can run into this exception. There are two solutions to this:
- Upgrade to JDK to 1.6.0_04 or above, which includes JAXB 2.1
- Copy JAXB 2.1 to <JAVA_HOME>/lib/endorsed to override the API jars that ship with the JDK