Now days I am learning ADF 11g and working on a sample example in Jdev 11g. For developers like me who had and still working on Oracle OAF and Oracle apps and what to learn ADF, it is very imporatnt to learn basic java, J2EE concepts as well as understanding XML and JSF concepts. Here are few links that I found usefull for learning these:-
--> Basic java - http://java.sun.com/docs/books/tutorial/java/index.html
--> J2EE - http://www.amazon.com/Certified-Component-Developer-Study-Companion/dp/0955160316
--> JSF - http://www.javapassion.com/j2ee/JSFBasics_speakernoted.pdf
--> XML concepts - http://www.w3schools.com/xml/default.asp
I will be posting my ADF 11g learning application by next year.