An interesting post on Timo Hohn's blog , which helps to avoid different version(s) of ADF Jdeveloper and Weblogic server :
http://tompeez.wordpress.com/2011/09/14/jdeveloper-versions-vs-weblogic-server-versions/
http://tompeez.wordpress.com/2011/09/14/jdeveloper-versions-vs-weblogic-server-versions/