Java Development Kit
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| Developer(s) | Sun Microsystems (Owned by Oracle Corporation) |
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| Stable release | 7 update 2 / December 12, 2011 |
| Operating system | Cross-platform |
| Type | Software development kit |
| License | Sun License (most of it also under GPL) |
| Website | https://jdk6.dev.java.net/ |
The Java Development Kit (JDK) is an Oracle Corporation 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]; Sun contributed the source code to the OpenJDK.
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JDK contents
The JDK has as its primary components a collection of programming tools, including:
- java – the loader for Java applications. This tool is an interpreter and can interpret the class files generated by the javac compiler. Now a single launcher is used for both development and deployment. The old deployment launcher, jre, no longer comes with Sun JDK, and instead it has been replaced by this new java loader.
- javac – the compiler, which converts source code into Java bytecode
- appletviewer – this tool can be used to run and debug Java applets without a web browser
- apt – the annotation-processing tool [1]
- extcheck – a utility which can detect JAR-file conflicts
- idlj – the IDL-to-Java compiler. This utility generates Java bindings from a given Java IDL file.
- javadoc – the documentation generator, which automatically generates documentation from source code comments
- jar – the archiver, which packages related class libraries into a single JAR file. This tool also helps manage JAR files.
- javah – the C header and stub generator, used to write native methods
- javap – the class file disassembler
- javaws – the Java Web Start launcher for JNLP applications
- jconsole – Java Monitoring and Management Console
- jdb – the debugger
- jhat – Java Heap Analysis Tool (experimental)
- jinfo – This utility gets configuration information from a running Java process or crash dump. (experimental)
- jmap – This utility outputs the memory map for Java and can print shared object memory maps or heap memory details of a given process or core dump. (experimental)
- jps – Java Virtual Machine Process Status Tool lists the instrumented HotSpot Java Virtual Machines (JVMs) on the target system. (experimental)
- jrunscript – Java command-line script shell.
- jstack – utility which prints Java stack traces of Java threads (experimental)
- jstat – Java Virtual Machine statistics monitoring tool (experimental)
- jstatd – jstat daemon (experimental)
- policytool – the policy creation and management tool, which can determine policy for a Java runtime, specifying which permissions are available for code from various sources
- VisualVM – visual tool integrating several command-line JDK tools and lightweight[clarification needed] performance and memory profiling capabilities
- wsimport – generates portable JAX-WS artifacts for invoking a web service.
- xjc – Part of the Java API for XML Binding (JAXB) API. It accepts an XML schema and generates Java classes.
Experimental tools may not be available in future versions of the JDK.
The JDK also comes with a complete Java Runtime Environment, usually called a private runtime, due to the fact that it is separated from the "regular" JRE and has extra contents. It consists of a Java Virtual Machine and all of the class libraries present in the production environment, as well as additional libraries only useful to developers, such as the internationalization libraries and the IDL libraries.
Copies of the JDK also include 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 forms an extended subset of a software development kit (SDK). In the descriptions which accompany its recent releases for Java SE, EE, and ME, Sun acknowledges that under its terminology, the JDK forms the subset of the SDK which has the responsibility for the writing and running of Java programs.[citation needed] The remainder of the SDK comprises 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.[contradiction] All of them adhere to the basic Java specifications, but they often differ in explicitly unspecified areas, such as garbage collection, compilation strategies, and optimization techniques. They include:
- GNU's GCJ (The GNU Compiler for Java)
- IBM J9 JDK, for AIX, Linux, Windows, MVS, OS/400, Pocket PC, z/OS [2]
- Oracle Corporation's JRockit JDK, for Windows, Linux and Solaris[citation needed]
- Blackdown Java – Port of Sun's JDK for Linux[citation needed]
- Apple's Mac OS Runtime for Java JVM/JDK for Classic Mac OS [3]
- Apache Harmony
- RedHat IcedTea, replacing the proprietary classpath[clarification needed] in OpenJDK
- Aicas JamaicaVM
See also
References
External links
- Oracle Java SE
- IBM Java technology JDK
- Open source JDK 7 project
- Open source JDK project
- Community support
- GNU Classpath – a Free software JDK alternative[citation needed]
- Javadoc Developer Kit (JDK) Search Engine
- Developer Support Services from Sun Microsystems
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