OpenJDK

OpenJDK is the official free implementation of the Java Platform, Standard Edition (Java SE ) ​​from Sun Microsystems, and provides the free successor to the Java Development Kit ( JDK) dar. It is and Java, written in C, is under the GNU General Public License ( GPL) with exceptions for linked external software and supported by well-known IT companies such as Apple, IBM and SAP.

History

After months of speculation since the disclosure of Solaris on a disclosure of Java Sun announced in May 2006 at the conference JavaOne that Java should be published in the source code under a free license free software. On 13 November 2006, the company began with the release of HotSpot, JavaHelp and the Java compiler javac, which is the core component of Java Development Kit to fulfill his promise. In May 2007, the publication of the bulk of the code of the class libraries were.

The steps were enthusiastically received in the free software world and hailed as milestones.

OpenJDK was created as a spin-off of version 6 of the JDK, so then the first versions of the 7 line were released as free software. In this case, a commercial version (or mainly related technical support services ) continue to be marketed, the first still contains at least the replaced in OpenJDK non-free components. Since also a need for a free implementation of the Java SE 6 consisted of OpenJDK OpenJDK 6 7 a was cleaved.

With OpenJDK7 Mac OS X is supported.

Substitutions proprietary parts

Since the acquisition of some code parts were not entirely owned by Sun, were the relevant parts only in compiled form and had to be replaced in order to obtain a completely free version.

This includes, among other things, the software for scanning two-dimensional vector graphics with support for anti-aliasing called Pisces. Pisces calculated for each element of the cover values ​​of the individual pixels, which are then passed on for further processing on the graphics processor, which then adds together the individual elements. It comes from Sun's reference implementation of a Java environment for mobile and embedded devices called phoneME, the free successor to the Java Platform, Micro Edition (Java ME), replacing the proprietary ductus previously used, the performance of ' is Pisces still clearly superior. As an alternative to Pisces ' pure software rendering can in OpenJDK now the graphics library Cairo are used which offers the possibility of hardware acceleration.

Furthermore, the non-free software synthesizer with a specially developed new development called Gervill code for scaling and rasterizing fonts has been replaced by the FreeType library, and color management software with the proven free LittleCMS.

IcedTea

In an independent Sun Community project called IcedTea ( which now also contributes to the official branch ) the creation of an executable completely free version of the OpenJDK was finally completed in a separate development branch, which even at their own creation by using the GNU Compiler for Java ( GCJ ) does not require the help of proprietary software. Here, the free code from OpenJDK has been with code from the GNU Classpath project ( free implementation of the standard class libraries) completed where proprietary remaining ingredients had left gaps that were not yet filled. In November 2007 IcedTea packages could be included in Fedora 8.

After the first implementation of the Java SE 7 has been implemented by IcedTea, came in April 2008, a variant called icedtea6 for version 6 of the Java SE specification. Since June 2008, the packages created by IcedTea are officially "Java Compatible" and may wear the protected name OpenJDK.

In Ubuntu 8.04 ( released April 24, 2008 ) and Fedora 9 (13 May 2008) OpenJDK was first included on the basis of icedtea6 and from Ubuntu 10.04 replaces the Sun JDK OpenJDK as the default.

With version b10 of openjdk6 (March 2008) and version b53 of OpenJDK7 (April 2009) could now also the official branch replace all the (relevant) remains proprietary.