Where can I find more diagnostic information about datastore behavior?

I'm using google app engine and its datastore to store a JDO Entity, called A. Class A has a @Persistent member of type B. I'm making changes to A, everything works fine... except this B member is nev开发者_如何学运维er recorded in the datastore (I don't think). Changes to B don't show up, every fetch I do has B has null even though I clearly set it to an instance of B before I makePersistent(theAInstance).

No errors are displayed anywhere. It just doesn't work. Is there any way to get a look at what is happening in dev mode, or enable some more verbose level of logging? I've been digging at this for an hour and it's driving me insane.

Turn the log level up perhaps ? its basic log4j so Log4J website (and DataNucleus website) should give plenty of info.