Free Java implementation

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A free Java implementation is an implementation of the Java platform as free software .

history

With Java technology as an important software platform (see Java platform ), on which numerous free software is based, the non-free implementations of the Java programming language that were necessary for a long time were seen as an ethically problematic gap in the free software ecosystem - Richard Stallman and the Free Software Foundation (FSF) spoke of the "Java trap". Therefore there was a need for free Java implementations, the implementation of which was pursued with high priority by the FSF and things like the free implementation of the standard class libraries GNU Classpath and the GNU Compiler for Java (GCJ), which also includes the GNU Interpreter for Java (GIJ ) contains.

Perhaps the first free implementation of essential parts of the Java platform is the Java compiler guavac , which was started before November 1995. In 2005 an attempt should be made with Harmony to combine the development efforts for free Java implementations in one project. Despite the fact that the close alliance did not succeed, the project lives on under the umbrella of the Apache Software Foundation and has resulted in a complete implementation.

With the publication of the official implementations by the manufacturer Sun Microsystems in 2006, this situation finally resolved after a few minor hurdles and the family of free Java implementations and the free software world as a whole were supplemented by a large and important package of software.

OpenJDK as the successor to the Java Development Kit (JDK) and many other components emerged as free Java implementations . Important branches of the OpenJDK development were and still are the versions of the IcedTea project. Besides these, there are coffee , which now slim as particularly fast alternative runtime environment continues to exist, which itself in turn written in Java Jikes RVM , the extremely small JamVM that developed for mono IKVM.NET and for the operating system Bluebottle written Jao .

Specialized implementations

There are also a number of specialized implementations.

For portable devices there are SuperWaba , Squawk and the Dalvik Virtual Machine from Android, Mysaifu JVM as the only actively further developed free Java SE compatible JVM for PocketPC. For special hardware platforms there is the NanoVM for Atmel AVR -ATmega8 microcontrollers , leJOS for Lego Mindstorms and Wonka VM and its successor Mika VM for embedded devices .

CACAO supports a number of platforms, and with its fast execution speeds due to JIT compilation it is probably the fastest Java implementation available on some.

There are also operating systems programmed in Java, such as B. JX (operating system) or JNode .

See also

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  1. ↑ Free but tied up - The Java Trap
  2. ↑ Change log of the guavac compiler  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link / www.sfr-fresh.com  
  3. ↑ Announcing: guavac 0.2.5 ( Memento of the original from August 14, 2009 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. - Announcement of the release of version 0.2.5 of guavac @1@ 2Template: Webachiv / IABot / www.ccs.neu.edu