# GNU Classpath > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/GNU_Classpath > Markdown URL: https://mediated.wiki/source/GNU_Classpath.md > Source: https://en.wikipedia.org/wiki/GNU_Classpath > Source revision: 1356813889 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Implementation of standard class library of Java This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "GNU Classpath" – news · newspapers · books · scholar · JSTOR (July 2023) (Learn how and when to remove this message) GNU Classpath Screenshot Demonstration of the GNU Classpath Swing Developers GNU Project (formally held by FSF) Final release 0.99[1] / March 16, 2012; 14 years ago (2012-03-16) Written in C and Java Operating system Cross-platform Type Library License GPL linking exception Website www.gnu.org/software/classpath/ Repository git.savannah.gnu.org/cgit/classpath.git **GNU Classpath** is a [free software](/source/Free_software) implementation of the standard [class library](/source/Java_Class_Library) for the [Java programming language](/source/Java_(programming_language)). Most classes from [J2SE](/source/Java_Platform%2C_Standard_Edition) 1.4 and 5.0 are implemented. Classpath can thus be used to run Java-based [applications](/source/Application_software). GNU Classpath is a part of the [GNU Project](/source/GNU_Project). It was originally developed in parallel with [libgcj](/source/GNU_Compiler_for_Java) due to license incompatibilities, but later the two projects merged. GNU Classpath was deemed a high priority project by the [Free Software Foundation](/source/Free_Software_Foundation). When the Classpath project began, the [license](/source/Software_license) for the official Java implementation from [Sun Microsystems](/source/Sun_Microsystems) did not allow distribution of any alterations. Since the inception of the Classpath project, the [OpenJDK](/source/OpenJDK) was released under the [GPL](/source/GNU_General_Public_License) and now serves as the official reference implementation for the [Java platform](/source/Java_platform). ## License GNU Classpath is licensed under the [GNU General Public License](/source/GNU_General_Public_License) with a [linking exception](/source/GPL_linking_exception). This is a [free software license](/source/Free_software_license). All code is formally owned by the [Free Software Foundation](/source/Free_Software_Foundation),[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] and this owner is bound by its own contractual obligations to the developers.[*[clarification needed](https://en.wikipedia.org/wiki/Wikipedia:Please_clarify)*] ## Uses GNU Classpath is used by many [free Java runtimes](/source/Free_Java_implementations) (like [Kaffe](/source/Kaffe), [SableVM](/source/SableVM), [JamVM](/source/JamVM), [Jikes RVM](/source/Jikes_RVM), and VMKit) because every full-featured Java virtual machine must provide an implementation of the standard class libraries. Some other uses include: - The [GNU Compiler for Java](/source/GNU_Compiler_for_Java), which is capable of compiling Java code into native standalone executables. - GCJAppletViewer[2] for launching [Java applets](/source/Java_applet) from command line if they are not supported by the browser in use. - [IKVM](/source/IKVM), which integrates Java with the [.NET Framework](/source/.NET_Framework) - JNode, an operating system for running Java applications. This system is written in Java and assembler only. - Specialised virtual machines such as [Jaos](https://web.archive.org/web/20080316045633/http://www.oberon.ethz.ch/jaos/) for integration with the [Oberon programming language](/source/Oberon_programming_language), and [JamaicaVM](/source/JamaicaVM) for embedded systems with real-time guarantees. - Virtual machines for distributed computing with clusters, having up to 128 processors on [Myrinet](/source/Myrinet).[3] - The [IcedTea](/source/IcedTea) project used GNU Classpath as a replacement for proprietary elements of [OpenJDK](/source/OpenJDK), prior to their replacement upstream. ## History GNU Classpath development started in 1998 with five developers.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] During the history, it merged several times with other projects having similar goals ([Kaffe](/source/Kaffe), libgcj). In the past, GNU Classpath supplied its own virtual machine (Japhar). As Classpath was becoming a base library, shared with a lot of different projects, this virtual machine received less and less attention and is now no longer supported.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] After implementing the majority of the official Java 1.4 API, the work in the project became more bug oriented rather than API coverage oriented. On October 24, 2006, the implementation of the last missing 1.4 class, [HTMLWriter](https://web.archive.org/web/20090715130332/http://java.sun.com/j2se/1.4.2/docs/api/javax/swing/text/html/HTMLWriter.html), was committed. The development speed (computed mathematically as the average number of the new [lines of code](/source/Source_lines_of_code) per day) reached its highest ever in 2006.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] The name GNU Classpath was originally suggested by [Bradley M. Kuhn](/source/Bradley_M._Kuhn) to one of the first developers, Paul Fisher. At the time, there was [great concern in the Free Java implementations community](/source/Free_Java_implementations) about enforcement of Sun's trademark on Java against free implementations. Kuhn suggested the name **$CLASSPATH**, which is the [environment variable](/source/Environment_variable) used by most Java systems to indicate where the Java libraries reside on the computer. Since **$CLASSPATH** often expanded to a [path name](/source/Path_(computing)) that included the word *java* (such as /usr/lib/java), it was a way to evoke the name *Java* without actually saying it. Fisher and other developers didn't like the unsightly use of the *$* and all capital letters and settled on *Classpath*. ## Development team The maintainer takes care of the legal side of the project, prepares the regular project releases and does some quality management. The maintainer also grants the [CVS](/source/Concurrent_Versions_System) access permissions.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] GNU Classpath has no formal hierarchy. The work is done by the most technically capable, and there is no strict work division either. All code changes are first posted to the discussion list as patches where they can be opposed if needed. The project typically receives between five and eight patches per day. The GNU Classpath library [code coverage](/source/Code_coverage) progress can be tracked against OpenJDK6[4] and OpenJDK7.[5] ## Virtual machine integration GNU Classpath contains classes from the official Java API namespace. Where calls to native code are necessary or highly desired, this is done from a small number of "VM" classes. The name of such a VM class matches the name of the class requiring native methods, plus the additional **VM** prefix: VMObject, VMString and so on. VM classes, stored separately from the rest of code, are [package private and final](/source/Java_syntax#Access_modifiers). The methods of these classes contain the keyword *native*, indicating the necessity of the supporting native library. Such libraries are provided by the authors of a Java virtual machine, hence GNU Classpath can be connected to nearly any Java virtual machine if the sources of such virtual machine are available and can be modified. ## Support for the new language features in Java 1.5 Before version 0.95, each GNU Classpath release consisted of two separate release tarballs; one that represented the state of the main [development branch](/source/Branching_(software)) and another that contained the contents of a more experimental branch, supporting the additions, such as generics, enumerations and annotations, present in Java 1.5.[6] Since version 0.95,[7] Java 1.5 additions like generics have been fully integrated into the main branch. The branch can be built by using the [Eclipse](/source/Eclipse_(software)) compiler, ecj, to compile Java 1.5 source code to bytecode. In the case of GCJ, it uses ecj to perform this initial stage, then converts the bytecode to native code. From 0.95 onwards, GNU Classpath also supports compiling and running the newly [GPLed](/source/GPL) open-source [javac](/source/Javac) [compiler](/source/Java_compiler) using GNU Classpath and also allows the GNU Classpath class library, tools and examples to be compiled with [javac](/source/Javac) itself. ## Classes from the omg.org domain Sun and GNU [Corba](/source/Common_Object_Request_Broker_Architecture) interact in a two client game[a] GNU Classpath does not accept any code that has a non-free license, or that was automatically generated from code with a non-free license. The standard Java API contains numerous classes from the omg.org domain that are normally generated from the [IDL](/source/Interface_definition_language) files, released by the [Object Management Group](/source/Object_Management_Group). The "use, but no modify" license of these files counts as non-free. For this reason, the mentioned classes in the GNU Classpath project were written from scratch, using only the official printed OMG specifications. Hence this part of GNU Classpath is as free as any other code in the project.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] ## See also - [Free and open-source software portal](https://en.wikipedia.org/wiki/Portal:Free_and_open-source_software) - [Computer programming portal](https://en.wikipedia.org/wiki/Portal:Computer_programming) - [Apache Harmony](/source/Apache_Harmony) - [GNU Compiler for Java](/source/GNU_Compiler_for_Java) - [IKVM](/source/IKVM) - [JamVM](/source/JamVM) - [JamaicaVM](/source/JamaicaVM) - [Jaos](https://web.archive.org/web/20080316045633/http://www.oberon.ethz.ch/jaos/) - [JikesRVM](/source/JikesRVM) - [Kaffe](/source/Kaffe) - [IcedTea](/source/IcedTea) - [Free Java implementations](/source/Free_Java_implementations) - [Java Class Library](/source/Java_Class_Library) ## Notes 1. **[^](#cite_ref-10)** Fosdem 2006 included this and other demonstrations of data exchange between Sun's and Classpath implementations of CORBA.[8] The source code is available[9] in the Classpath repository. ## References 1. **[^](#cite_ref-1)** Hughes, Andrew John (2012-03-16). ["GNU Classpath 0.99 Released!"](https://web.archive.org/web/20121214141527/http://blog.fuseyism.com/index.php/2012/03/16/gnu-classpath-0-99-released/) ([World Wide Web](/source/World_Wide_Web) log). Fuseyism. Archived from [the original](http://blog.fuseyism.com/index.php/2012/03/16/gnu-classpath-0-99-released/) on 2012-12-14. Retrieved 2012-03-20. 1. **[^](#cite_ref-2)** [*GCJ applet viewer*](https://web.archive.org/web/20090918100934/http://www.koders.com/java/fid00976F58DD49540480F81EB78F2C2492A3393CD1.aspx), Koders, archived from [the original](http://www.koders.com/java/fid00976F58DD49540480F81EB78F2C2492A3393CD1.aspx) on 2009-09-18, retrieved 2009-09-14. 1. **[^](#cite_ref-3)** "Jupiter", [*EECG*](http://www.eecg.toronto.edu/jupiter/), U Toronto. 1. **[^](#cite_ref-4)** "GNU Classpath Library Coverage against OpenJDK6", [*J API*](https://web.archive.org/web/20150906132808/http://fuseyism.com/japi/icedtea6-classpath.html), Fuseyism, archived from [the original](http://fuseyism.com/japi/icedtea6-classpath.html) on 2015-09-06, retrieved 2012-05-31. 1. **[^](#cite_ref-5)** "GNU Classpath Library Coverage against OpenJDK7", [*J API*](https://web.archive.org/web/20160304051651/http://fuseyism.com/japi/icedtea7-classpath.html), Fuseyism, archived from [the original](http://fuseyism.com/japi/icedtea7-classpath.html) on 2016-03-04, retrieved 2012-05-31. 1. **[^](#cite_ref-generics-release_6-0)** "GNU Classpath "95% and counting" 0.19 released", [*The GNU Project*](https://www.gnu.org/software/classpath/announce/20051102.html) (announcement), Software, The Free Software Foundation, 2005-11-02, retrieved 31 May 2011. 1. **[^](#cite_ref-release_7-0)** "The release of GNU Classpath 0.98 "Better Late Than Never", [*The GNU Project*](https://www.gnu.org/software/classpath/announce/20090205.html) (announcement), Software, The Free Software Foundation, 2009-02-05. 1. **[^](#cite_ref-8)** [*Fosdem*](http://developer.classpath.org/mediation/Fosdem2006) (conference archive), Classpath, 2006. 1. **[^](#cite_ref-9)** "Classpath", [*The GNU is Not Unix Project*](http://cvs.savannah.gnu.org/viewvc/classpath/examples/gnu/classpath/examples/CORBA/swing/x5/?root=classpath) (source code) (example), The Free Software Foundation. ## External links - [Official website](https://www.gnu.org/software/classpath/) - "Automatically generated documentation, including source code", [*Classpath*](http://developer.classpath.org/doc/). - "Builder", [*Classpath*](https://web.archive.org/web/20130502200707/http://builder.classpath.org/), archived from [the original](http://builder.classpath.org/) on 2013-05-02, retrieved 2013-03-02: test runs and binary compatibility tests - A GNU Classpath developer (May 2006), ["The state of free java project collaborations"](https://lwn.net/Articles/184967/), *GNU/Linux weekly news* (article). - "Permeable Development", [*SMI*](https://web.archive.org/web/20060720171116/http://public.smi.ethz.ch/blog/2006/01/25/permeable-development/) ([World Wide Web](/source/World_Wide_Web) log), [CH](/source/Switzerland): ETHZ, 2006-01-25, archived from [the original](http://public.smi.ethz.ch/blog/2006/01/25/permeable-development/) on 2006-07-20. v t e Java (software platform) Platforms Java ME (Micro) Java SE (Standard) Jakarta EE (Enterprise) Java Card Android SDK Technologies Sun/Oracle JDK OpenJDK JVM HotSpot Graal Maxine Squawk JavaFX Platform Applets Servlets MIDlets JSP JSF Web Start (JNLP) Pack200 Modules Major third-party ART Blackdown Eclipse GNU Classpath GWT Harmony Hibernate IcedTea Jazelle OpenJ9 Spring Struts TopLink WildFly History Java version history Java Community Process Sun Microsystems Free Java implementations Slogan: Write once, run anywhere Platform languages Java BeanShell Clojure Groovy JRuby Jython Kotlin Processing Rhino Scala Oxygene Community Conferences JavaOne Devoxx Organizations Apache Software Foundation Eclipse Foundation Java Community Process Oracle Corporation Sun Microsystems, Sun Microsystems Laboratories People James Gosling Arthur van Hoff Urs Hölzle Computer programming portal • Category v t e GNU Project History GNU Manifesto Free Software Foundation Europe India Latin America History of free software Licenses GNU General Public License linking exception font exception GNU Lesser General Public License GNU Affero General Public License GNU Free Documentation License GNAT Modified General Public License Software GNU (variants) Hurd Linux-libre glibc Bash coreutils findutils Build system GCC binutils GDB GRUB GNUstep GIMP Jami GNU Emacs GNU TeXmacs GNU Octave GNU Taler GNU R GSL GMP GNU Electric GNU Archimedes GNUnet GNU Privacy Guard Gnuzilla (IceCat) GNU Health GNUmed GNU LilyPond GNU Go GNU Chess Gnash Guix more... Contributors Benjamin Mako Hill Bradley M. Kuhn Brian Fox Federico Heinz John Sullivan Richard M. Stallman Other topics GNU/Linux naming controversy Revolution OS Free Software Foundation anti-Windows campaigns Defective by Design --- Adapted from the Wikipedia article [GNU Classpath](https://en.wikipedia.org/wiki/GNU_Classpath) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/GNU_Classpath?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.