Core Java refers to the fundamental concepts of the Java programming language. It is the most basic edition of Java and is used mainly for developing desktop applications and server-based applications. Core Java is a subset of Java SE technology that includes both general-purpose and specific-purpose APIs. It covers all the basic and fundamental Java programming language concepts, including data types, OOP, operators, exception handling, swing, threading, and collections. Core Java is not different from Java, but it is the foundation for all other Java editions. Java SE is a computing-based platform and used for developing desktop or window-based applications. Thus, Core Java is the part of Java SE where developers develop desktop-based applications by using the basic concepts of Java where JDK (Java Development Kit) is a quite familiar Java SE implementation.