I mistakenly put oracle Root logger to finest which of course crashed everything. So I restarted JDev then restarted Weblogic horror the setting was still set.
Great so now I could not work.
Solution (thanks google and this oracle doc ): located the logging.xml file in your integrated weblogic server:
Edit it and remove the offending log leve setting. (mine was <logger name='oracle'/ level='FINEST'> ==> <logger name='oracle'/>)
All fixed and working again...