The Java Development Kit (JDK) is a Sun Microsystems product aimed at Java developers. Since the introduction of Java, it has been by far the most widely used Java SDK. On 17 November 2006, Sun announced that it would be released under the GNU General Public License (GPL), thus making it free software. This happened in large part on 8 May 2007^[1] and the source code was contributed to the OpenJDK community.

Contents 1 JDK contents 2 Ambiguity between a JDK and an SDK 3 Other JDKs 4 References 5 See also 6 External links

JDK contents

The primary components of the JDK are a selection of programming tools, including:

• javac – The compiler, which converts source code into Java bytecode
• jar – The archiver, which packages related class libraries into a single JAR file
• javadoc – The documentation generator, which automatically generates documentation from source code comments
• jdb – The debugger

The JDK also comes with a complete Java Runtime Environment, usually called a private runtime. It consists of a Java Virtual Machine and all of the class libraries that will be present in the production environment, as well as additional libraries only useful to developers, such as the internationalization libraries and the IDL libraries.

Also included are a wide selection of example programs demonstrating the use of almost all portions of the Java API.

Ambiguity between a JDK and an SDK

The JDK is a subset of what is loosely defined as a Software development kit (SDK) in the general sense. In the descriptions which accompany their recent releases for Java SE, EE, and ME, Sun acknowledge that under their terminology, the JDK forms the subset of the SDK which is responsible for the writing and running of Java programs. The remainder of the SDK is composed of extra software, such as Application Servers, Debuggers, and Documentation.

Other JDKs

There are other JDKs commonly available for a variety of platforms, some of which started from the Sun JDK source and some which did not. All of them adhere to the basic Java specifications, but they often differ in areas that are explicitly unspecified, such as garbage collection, compilation strategies, and optimization techniques. They include:

• IBM's J9 JDK, for AIX, Linux, MVS, OS/400, Pocket PC, z/OS [1]
• Blackdown Java – The Blackdown Group's port of Sun's JDK for Linux
• Apple's MacOS Runtime for Java JVM/JDK for Mac OS X [2]

References

See also

• Java platform
• Classpath (Java)
• Java Virtual Machine

External links

• Sun Java SE – Sun's current stable release (6).
• [3] Open source JDK 7 project
• [4] Open source JDK project
• [5] Community support
• GNU Classpath – a free JDK replacement.
• Apache Harmony under the Apache License 2.0
• BEA JRockit – BEA's JDK.
• [6] Javadoc Developer Kit (JDK) Search Engine.

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