Java is a programming language, whereas Core Java is a computing platform. Java Platform Standard Edition is Core Java, which is also called Java SE. The following are the computing following supported by Java, which also has Core Java as its part:
Java Standard Edition used to develop desktop applications. A well-known implementation of Java SE is the Java Development Kit (JDK).
Java Enterprise Edition i.e. Java 2 Platform, Enterprise Edition or J2EE. Java EE is used for applications running on servers.
Java Micro Edition is used for applications running on mobile phones.
Java SE is the Standard Edition and also called as Core Java, which is eventually a part of Java.