Java Development Kit

<h2 id="jdk-contents">JDK contents</h2>
The JDK has as its primary components a collection of programming tools, including:

<ul><li><a href="/facts/AppletViewer/nK6JzjsT">appletviewer</a> – this tool can be used to run and debug Java applets without a web browser</li>
<li>apt – the <a href="/facts/Metadata_facility_for_Java/kJECWfHB">annotation-processing tool</a><a class="footnote-ref" id="fnref:2" href="#fn:2">2</a></li>
<li>extcheck – a utility that detects JAR file conflicts</li>
<li>idlj – the IDL-to-Java compiler. This utility generates Java <a href="/facts/Language_binding/V5HW4Wr4">bindings</a> from a given <a href="/facts/Java_Interface_Definition_Language/4o0gJlol">Java IDL</a> file.</li>
<li>jabswitch – the <a href="/facts/Java_Access_Bridge/2mbW0XGm">Java Access Bridge</a>. Exposes assistive technologies on Microsoft Windows systems.</li>
<li>java – the <a href="/facts/Loader_(computing)/eIK4f2xB">loader</a> for Java applications. This tool is an interpreter and can interpret the class files generated by the <a href="/facts/Javac/PhoCVLnM">javac</a> compiler. Now a single launcher is used for both development and deployment. The old deployment launcher, jre, no longer<a href="https://en.wikipedia.org/w/index.php?title=Java_Development_Kit&action=edit">[update]</a> comes with Sun JDK, and instead it has been replaced by this new java loader.</li>
<li><a href="/facts/Javac/PhoCVLnM">javac</a> – the <a href="/facts/Java_compiler/ajRWJnlW">Java compiler</a>, which converts source code into <a href="/facts/Java_bytecode/Nh1qKH4y">Java bytecode</a></li>
<li><a href="/facts/Javadoc/pm72Xvlf">javadoc</a> – the documentation generator, which automatically generates documentation from <a href="/facts/Source_code/o9J6Jv23">source code</a> comments</li>
<li><a href="/facts/JAR_(file_format)/LcIBCWXT">jar</a> – the archiver, which packages related class <a href="/facts/Library_(computer_science)/xRzL3P7q">libraries</a> into a single <a href="/facts/JAR_(file_format)/LcIBCWXT">JAR file</a>. This tool also helps manage JAR files.</li>
<li>javafxpackager – tool to package and sign JavaFX applications</li>
<li>jarsigner – the jar signing and verification tool</li>
<li>javah – the C header and stub generator, used to write native methods</li>
<li>javap – the class file <a href="/facts/Disassembler/4PR39BbK">disassembler</a></li>
<li>javaws – the <a href="/facts/Java_Web_Start/HPWVy5VS">Java Web Start</a> launcher for JNLP applications</li>
<li><a href="/facts/JConsole/6NxnTePw">JConsole</a> – Java Monitoring and Management Console</li>
<li>jdb – the <a href="/facts/Debugger/mCe6UsWj">debugger</a></li>
<li>jhat – Java Heap Analysis Tool (experimental)</li>
<li>jinfo – This utility gets configuration information from a running Java process or crash dump. (experimental)</li>
<li>jmap <a href="http://docs.oracle.com/javase/7/docs/technotes/tools/share/jmap.html">Oracle jmap – Memory Map</a>– 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)</li>
<li>jmc – Java Mission Control</li>
<li>jpackage – a tool for generating self-contained application bundles. (experimental)</li>
<li>jps – Java Virtual Machine Process Status Tool lists the instrumented HotSpot Java Virtual Machines (JVMs) on the target system. (experimental)</li>
<li>jrunscript – Java command-line <a href="/facts/Shell_script/NE7YvsBD">script</a> <a href="/facts/Shell_(computing)/Sa67elS7">shell</a>.</li>
<li><a href="/facts/Jshell/z1TPXqcF">jshell</a> – a <a href="/facts/Read%25E2%2580%2593eval%25E2%2580%2593print_loop/lddjCYxt">read–eval–print loop</a>, introduced in Java 9.</li>
<li>jstack – utility that prints Java <a href="/facts/Stack_trace/EupTJx5z">stack traces</a> of Java threads (experimental)</li>
<li>jstat – <a href="/facts/Java_virtual_machine/l9Nzrsun">Java Virtual Machine</a> statistics monitoring tool (experimental)</li>
<li>jstatd – jstat daemon (experimental)</li>
<li><a href="/facts/Keystore/Nh2pGjfD">keytool</a> – tool for manipulating the <a href="/facts/Keystore/Nh2pGjfD">keystore</a></li>
<li><a href="/facts/Pack200/m6qXWruv">pack200</a> – JAR compression tool</li>
<li>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.</li>
<li><a href="/facts/VisualVM/5AV3HWTk">VisualVM</a> – visual tool integrating several <a href="/facts/Command-line_interface/R9JpGmXQ">command-line</a> JDK tools and lightweight performance and memory <a href="/facts/Profiling_(computer_programming)/JbSlDHPP">profiling</a> capabilities (no longer included in JDK 9+)</li>
<li>wsimport – generates portable <a href="/facts/JAX-WS/xcIMaPgp">JAX-WS</a> artifacts for invoking a web service.</li>
<li>xjc – Part of the Java API for XML Binding (JAXB) API. It accepts an XML schema and generates Java classes.</li></ul>
Experimental tools may not be available in future versions of the JDK.
The JDK also comes with a complete <a href="/facts/Java_Runtime_Environment/l9Nzrsun">Java Runtime Environment</a> (JRE), 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 <a href="/facts/Java_virtual_machine/l9Nzrsun">Java virtual machine</a> and all of the class libraries present in the production environment, as well as additional libraries only useful to developers, such as the <a href="/facts/Internationalization_and_localization/IGkl9VBM">internationalization</a> libraries and the <a href="/facts/Interface_description_language/FpByLf4X">IDL</a> libraries.
Copies of the JDK also include a wide selection of example programs demonstrating the use of almost all portions of the <a href="/facts/Java_API/nRY3qexv">Java API</a>.

<h2 id="other-jdks">Other JDKs</h2>
In addition to the most widely used JDK discussed in this article, there are other JDKs commonly available for a variety of platforms, some of which started from the Sun JDK source and some that did not. All adhere to the basic Java specifications, but often differ in explicitly unspecified areas, such as garbage collection, compilation strategies, and optimization techniques. They include:
In development or in maintenance mode:

<ul><li><a href="/facts/Azul_Systems/WQwozozw">Azul Systems</a> Zing, low latency JDK for Linux;<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a></li>
<li><a href="/facts/Azul_Systems/WQwozozw">Azul Systems</a> / <a href="/facts/OpenJDK/KDzob3aF">OpenJDK</a>-based Zulu for Linux, Windows, Mac OS X, embedded and the cloud;<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a></li>
<li><a href="/facts/OpenJDK/KDzob3aF">OpenJDK</a> / <a href="/facts/IcedTea/H0Q5M5LI">IcedTea</a>;</li>
<li>Aicas <a href="/facts/JamaicaVM/2jFfIenc">JamaicaVM</a>;</li>
<li><a href="/facts/IBM_J9/CH4YJdDt">IBM J9</a> JDK, for AIX, Linux, Windows, MVS, OS/400, Pocket PC, z/OS;<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a></li></ul>
Not being maintained or discontinued:

<ul><li><a href="/facts/Apache_Harmony/wNJJJxVT">Apache Harmony</a>;</li>
<li><a href="/facts/Apple_Computer/oTJYta3k">Apple</a>'s <a href="/facts/Mac_OS_Runtime_for_Java/GpeBTNCB">Mac OS Runtime for Java</a> JVM/JDK for Classic <a href="/facts/Mac_OS/EkobAhow">Mac OS</a>;<a class="footnote-ref" id="fnref:6" href="#fn:6">6</a></li>
<li><a href="/facts/Blackdown_Java/kjeLG5hG">Blackdown Java</a> – Port of Sun's JDK for Linux;<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a><a class="footnote-ref" id="fnref:8" href="#fn:8">8</a></li>
<li><a href="/facts/GNU/HlAKKBdt">GNU</a>'s <a href="/facts/GNU_Classpath/rMSHp6ce">Classpath</a> and <a href="/facts/GNU_Compiler_for_Java/dzF8Ryvl">GCJ</a> (The <a href="/facts/GNU_Compiler_for_Java/dzF8Ryvl">GNU Compiler for Java</a>);</li>
<li><a href="/facts/Oracle_Corporation/0z14FygH">Oracle Corporation</a>'s <a href="/facts/JRockit/LkvkJ6gb">JRockit</a> JDK, for Windows, Linux, and Solaris;<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a></li></ul>
<h2 id="see-also">See also</h2>
<ul>
<li>Free and open-source software portal</li><li>Computer programming portal</li></ul>
<ul><li><a href="/facts/Classpath/Gmsj515v">Classpath</a></li>
<li><a href="/facts/Java_(software_platform)/fpn6x8WL">Java platform</a></li>
<li><a href="/facts/Java_version_history/Br6eHSP8">Java version history</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://www.oracle.com/technetwork/java/javase/">Oracle Java SE</a></li>
<li><a href="https://www.oracle.com/technetwork/java/javase/eol-135779.html">Oracle Java SE Support Roadmap</a></li>
<li><a href="https://openjdk.java.net/">Open source OpenJDK project</a></li>
<li><a href="https://jdk.java.net/">OpenJDK builds from Oracle</a></li>
<li><a href="https://adoptopenjdk.net/">OpenJDK builds from AdoptOpenJDK</a></li>
<li><a href="https://www.ibm.com/support/pages/java-sdk-downloads">IBM Java SDK Downloads</a></li>
<li><a href="https://web.archive.org/web/20070610111552/https://jdk7.dev.java.net/">Open source JDK 7 project</a></li>
<li><a href="https://www.gnu.org/software/classpath/">GNU Classpath</a> – a <a href="/facts/Free_software/IaoVtJXn">Free software</a> JDK alternative</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">"OpenJDK FAQ". OpenJDK. Archived from the original on 7 December 2021. Retrieved 23 October 2021. <a href="https://web.archive.org/web/20211207090911/https://openjdk.java.net/faq/" target="_blank">https://web.archive.org/web/20211207090911/https://openjdk.java.net/faq/</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">"JDK 5.0 Java Annotation Processing Tool (APT)-related APIs & Developer Guides -- from Sun Microsystems". Retrieved 5 August 2012. <a href="http://download.oracle.com/javase/1.5.0/docs/guide/apt/index.html" target="_blank">http://download.oracle.com/javase/1.5.0/docs/guide/apt/index.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">"Azul Zing product page". <a href="http://www.azulsystems.com/products/zing/whatisit" target="_blank">http://www.azulsystems.com/products/zing/whatisit</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">"Azul Zulu download page". <a href="http://www.azulsystems.com/products/zulu/downloads" target="_blank">http://www.azulsystems.com/products/zulu/downloads</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">"developerWorks : IBM developer kits : Downloads". Retrieved 5 August 2012. <a href="http://www-128.ibm.com/developerworks/java/jdk/" target="_blank">http://www-128.ibm.com/developerworks/java/jdk/</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">"Support at Apple". Archived from the original on 13 December 2007. <a href="https://web.archive.org/web/20071213085940/http://docs.info.apple.com/article.html?artnum=120209" target="_blank">https://web.archive.org/web/20071213085940/http://docs.info.apple.com/article.html?artnum=120209</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">"Java Linux Contact Information". Archived from the original on 7 August 2007. Retrieved 5 August 2012. <a href="https://web.archive.org/web/20070807032743/http://www.blackdown.org/java-linux/java-linux-contact.html" target="_blank">https://web.archive.org/web/20070807032743/http://www.blackdown.org/java-linux/java-linux-contact.html</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">"Java-Linux Latest Information". Archived from the original on 19 October 1996. Retrieved 5 August 2012. <a href="https://web.archive.org/web/19961019171456/http://www.blackdown.org/java-linux/Information.html" target="_blank">https://web.archive.org/web/19961019171456/http://www.blackdown.org/java-linux/Information.html</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">"JRockit Family Download page". Retrieved 5 August 2012. <a href="http://www.oracle.com/technetwork/middleware/jrockit/downloads/index.html" target="_blank">http://www.oracle.com/technetwork/middleware/jrockit/downloads/index.html</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
</ol>

Java Development Kit open-in-new

Java Development Kit