If you are using Ant 1.7.1 for developing Web Services with JAX-WS/JAXB, I suggest you to move to the latest version Ant 1.8.0.
JAXB/JAX-WS rely on package level runtime annotations for lot of things. For ex: JAXB relies on the @XmlSchema annotation in package-info.java and uses it for binding Java data types to XML schema types. You might be puzzled to see that the mappings are not as expected. I wasted almost half a day trying to figure out if there was some regression in JAX-WS/JAXB as I was suspecting Ant the least. A bug in Ant 1.7.1 javac ant task, makes it not compile package-info.java. This is a serious regression and the impact is not directly obvious until you see the behavior change in this case. The issue is resolved in Ant 1.8.0 and I encourage all JAXB/Metro users to use Ant 1.8.0 for development.