Core Java is Java SE;
Standard Edition[
^], where as Java is the language. Java is used not only for desktop applications, but for enterprise solutions; web servers programming and at the same time for mobile application development.
Java for other platforms is known as Java EE (
Enterprise Edition[
^]) and Java ME (
Millennium Edition[
^]; known as Micro edition). Core Java can also mean the basic libraries of Java; Enterprise of Millennium editions have some extra toppings on the top of Core Java.