Sun's software-development package that implements the basic set of tools needed to write, test, and debug Java applications and applets. It consists of a compiler, a debugger, and a run-time interpreter (virtual machine) for each particular platform. JDK also refers generally to the set of Sun-supplied classes, including the Abstract Windowing Toolkit.
A set of tools developed by Sun to help popularize the Java programming language.
The collection of Java classes, runtime, compiler, debugger, and usually source code for a version of Java that makes up a Java development environment. JDKs are designated by versions, and Java 2 is used to designate versions from 1.2 onward.