I am a beginner and wanted to know the difference between core Java and advance Java???

Answer 1

It's not actually a difference... Just, you have to learn the basis first (core Java) and then you can do difficult things (like IHM, network connectivity or AI programming,...). Just like in mathematics, it's better to learn 2+2=4 before doing differential equations... But the limit is not really clear.

Answer 2

Java core (or just basics) is like walking,
and the advance is like running and jumping,
you first learn how to walk and then how to run then how jump,
with the core you starting with simple things like how to do loops and creating classes, with advanced you starting to use and implement other methods and librarys to achieve greater things like AI, external connection, and many more.
with a bit of thinking and practice there is nothing you can't do