Basic

which are core java topics and which are advanced java topics

In which context? There is no commonly accepted notion of "core java" and "advanced java".

I agree. That may change depending on who you talk to. However, a good place to start may be looking at the contents of Sun's "Core Java books:

Core Java(TM) 2, Volume I--Fundamentals (7th Edition) (Core Series)
Core Java(TM) 2, Volume II--Advanced Features (7th Edition) (Core Series)

by Cay S. Horstmann and Gary Cornell

I don't think there is any kind of official or sanctioned idea or notion of "Core Java."

I nearly said that core Java is on page 1 and advanced on page 82365876.

There are some things in Core Java (Horstmann and Cornell-excellent book but maybe not for the beginner) vol I, eg reflection, which a lot of people would regard as "advanced" topics.

Yes, as it is a "subjective" topic to discuss and debate, i presume the "basics of java" might have been interpreted and used as "core java". Is that right?