The information that you can see in V$SGASTAT comes from X$KSMJS, and X$KSMJCH has the details for all the used chunks. Also, have you noticed the presence of X$JOXFC, X$JOXFR, X$JOXFS and X$JOXFT for information about the contents of the Java objects? I am not doing any work with Java stuff at the moment, so I cannot yet help you much with the interpretation of what you'll find there. Have fun.

I am looking to find some information in the 8.1.6 Data dictionary about memory usage by Java Objects.

Where should I be looking. (I can see the Java Pool and large pool through v$sgastat, but am looking for a bit more detailed info).