Apache Harmony

Apache Harmony
Developer(s) Apache Software Foundation
Stable release
5.0M15
6.0M3 / September 15, 2010 (2010-09-15)
Development status Discontinued[1]
Written in C++, Java
Operating system Windows, Linux
Type Java Virtual Machine, Java Library
License Apache License 2.0
Website harmony.apache.org

Apache Harmony is a retired open source, free Java implementation, developed by the Apache Software Foundation.[2] It was announced in early May 2005 and on October 25, 2006, the Board of Directors voted to make Apache Harmony a top-level project. The Harmony project achieved (as of February 2011) 99% completeness for J2SE 5.0, and 97% for Java SE 6.[3] The Android operating system has historically been a major user of Harmony, however since Android Nougat, it uses OpenJDK libraries gaining, e.g., some features of Java 8 (that is, excluding its JVM).[4]

On October 29, 2011 a vote was started by the project lead Tim Ellison whether to retire the project. The outcome was 20 to 2 in favor,[5] and the project was retired on November 16, 2011.[6]

History

Initiation

The Harmony project was initially conceived as an effort to unite all developers of the free Java implementations. Many developers expected that it would be the project above the GNU, Apache and other communities. GNU developers were invited into and participated during the initial, preparatory planning.[7]

Incompatibility with GNU Classpath

Despite the impression given by the preparatory planning, it was decided not to use the code from GNU Classpath, and that Harmony would use an incompatible license; therefore blocking the collaboration between Harmony and existing free Java projects.[8] Apache developers would then write the needed classes from scratch and expect necessary large code donations from software companies. Various misunderstandings at the start of the project, and the fact that major companies like IBM proposed to give large amount of existing code, created some confusion in the free Java community about the real objectives of the project.[9]

One major point of incompatibility between the GNU Classpath and Apache Harmony projects was their incompatible licenses: Classpath's GNU General Public License with the linking exception versus Harmony's Apache License.[9]

Difficulties to obtain a TCK license from Sun

On April 10, 2007, the Apache Software Foundation sent an open letter to Sun Microsystems CEO, Jonathan Schwartz regarding their inability to acquire an acceptable license for the Java SE 5 Technology Compatibility Kit (TCK), a test kit needed by the project to demonstrate compatibility with the Java SE 5 specification, as needed by the Sun specification license for Java SE 5.[10] What makes the license unacceptable for ASF is the fact that it imposes rights restrictions through limits on the "field of use" available to users of Harmony, not compliant with the Java Community Process rules.[11]

Sun answered on a company blog[12][13] that it intended to create an open source implementation of the Java platform under GPL, including the TCK, but that their current priority was to make the Java Platform accessible to the GNU/Linux community under GPL as quickly as possible.

This answer triggered some reactions, either criticizing Sun for not responding "in a sufficiently open manner" to an open letter,[14] or rather Apache Software Foundation; some think that ASF acted unwisely to aggressively demand something they could have obtained with more diplomacy from Sun, especially considering the timescale of the opening class library.[15][16]

Since Sun's release of OpenJDK, Sun has released a specific license to allow to run the TCK in the OpenJDK context for any GPL implementation deriving substantially from OpenJDK.[17]

On December 9, 2010, the Apache Software Foundation resigned from the Java Community Process Executive Committee,[18] in protest over the difficulty in obtaining a license acceptable to Apache for use with the Harmony project.[19]

Use in Android SDK

The virtual machine that is used in Google's Android platform (Dalvik up to version 4.4 and Android Runtime (ART), that followed), uses a subset of Harmony for the core of its Class Library.[20][21] However, Dalvik does not align to Java SE nor Java ME Class Library profiles (for example J2ME classes, AWT and Swing are not supported).

Android 7.0 "Nougat" replaced Harmony with OpenJDK.[4]

Disengagement from IBM

On October 11, 2010, IBM, by far the biggest participant in the project, decided to join Oracle on the OpenJDK project, effectively shifting its efforts from Harmony to the Oracle reference implementation.[22][23] Bob Sutor, IBM's head of Linux and open source, blogged that "IBM will be shifting its development effort from the Apache Project Harmony to OpenJDK".[24]

On March 2011, IBM's Tim Ellison announced that he resigned as Project Management Chair for Harmony, a move which brought questions about the future of the project.[25][26] Since the beginning of 2011, there has been almost no more development on the project, nor discussions on the mailing list.[27]

End of the project

On October 29, 2011, a poll was started on the harmony-dev mailing list by the project lead Tim Ellison whether to retire the project. The outcome on November 3, was 20 to 2 in favor of retirement.[5] On November 16, 2011, the Apache Software Foundation board of directors passed a motion to terminate the project.[28] One director, Larry Rosen, cast a "no" vote, based on the timing rather than the merits of the proposal; it was otherwise unanimous.[28] The project was retired on November 16, 2011.[6]

Development team

At the start, Apache Harmony received some large code contributions from several companies. Development discussions have taken place on open mailing lists. Later, the Apache Software foundation mentors put a lot of effort into bringing the development process more in line with "the Apache way,"[29][30] and it seemed that their efforts were successful.

Last development status

Apache Harmony was accepted among the official Apache projects on October 29, 2006.

Architecture

The Dynamic Runtime Layer virtual machine consists of the following components:

  1. The VM core: with its subcomponents concentrates most of the JVM control functions.
  2. The porting layer: hides platform-specific details from other VM components behind a single interface and is based on the Apache Portable Runtime layer.
  3. The garbage collector: allocates Java objects in the heap memory and reclaims unreachable objects using various algorithms
  4. Execution Manager: selects the execution engine for compiling a method, handles profiles and the dynamic recompilation logic.
  5. Class Library: is a Java standard library.
  6. The thread manager that handle operating system threading
  7. The execution engine: consists of the following:
    1. The just-in-time compiler for compilation and execution of method code.
    2. The interpreter for easier debugging.

Support platform and operating system

The project provided a portable implementation that ease development on many platforms and operating systems. The main focus was on Windows and Linux operating systems on x86 and x86-64 architectures.[31]

Windows 2000 Windows XP, Server 2003, Vista Linux RHEL, SLES, Debian, Gentoo, Fedora FreeBSD AIX Mac OS X
IA-32 (Pentium III or better) No Yes Yes No N/A N/A
x86-64 (Intel 64, AMD64) N/A Yes Yes N/A N/A N/A
Itanium (IA64, IPF) N/A No Yes N/A N/A N/A
PowerPC 32-bit N/A N/A No N/A N/A N/A
PowerPC 64-bit N/A N/A No N/A No N/A
zSeries 31-bit N/A N/A No N/A N/A N/A

Class library coverage

The expected donations from software companies were actually received. The Apache Harmony now contains the working code, including the Swing, AWT and Java 2D code which were contributed by Intel.

The Harmony project currently achieve (as of February 2011) 99% completeness for JDK 5.0, and 97% for Java SE 6.[3]

The progress of the Apache Harmony project can be tracked against J2SE 1.4 and Java SE 5.0.[32] Also, there is a branch for Harmony v6.0 in development for Java SE 6.0.

Apache Harmony developers integrate several existing, field-tested open-source projects to meet their goal (not reinventing the wheel). Many of these projects are mature and well known and other parts of the library needed to be written from scratch.

This is a list of existing open source components that are used in the Apache Harmony project; some of them were in use before the project started.

Component Description
ICU Mature C/C++ and Java libraries for Unicode support and software internationalization and globalization
Apache Xalan XSLT stylesheet processor for Java, C++ which implements XPath language
Apache Xerces XML parser library for Java, C++, Perl
Apache Portable Runtime Cross-platform abstraction library, provides platform independence
Apache CXF Robust, high performance Web services framework work over protocols such as SOAP, XML/HTTP, RESTful HTTP, CORBA
BCEL Libraries to decompose, modify, and recompose binary Java classes, i.e., bytecode
MX4J Java Management Extensions (JMX) tools to manage and monitor applications, system objects, devices and service-oriented networks
VM Magic Set of extensions to Java language to facilitate systems programming in Java by adding direct memory operations, etc.
Bouncy Castle Libraries collection of lightweight cryptography for Java and C#
ANTLR Language tool, provides a framework to construct recognizers, interpreters, compilers, and translators from grammatical descriptions containing actions in many target languages

Documentation

Harmony is currently less documented than the alternative free Java implementations. For instance, in GNU Classpath every method of the central CORBA class (ORB) has the explaining comment both in the standard abstract API class[33] and implementation.[34] In the Yoko project, used by Harmony,[35] most methods both in the standard declaration[36] and implementing class[37] were undocumented at the end of October 2006. Also, GNU Classpath supported both older and current CORBA features (same as Sun's implementation). Harmony, differently, left the central method of the older standard (ORB.connect(Object)) fully unimplemented.

Tools

A complete implementation of the Java platform also needs a compiler that translates Java source code into bytecodes, a program that manages JAR files, a debugger, and an applet viewer and web browser plugin, to name a few. Harmony currently has the compiler, appletviewer, jarsigner, javah, javap, keytool, policytool, and unpack200 .

Virtual machine support

Harmony currently has seven virtual machine implementations that run Harmony Class Library, all of which were donations by external groups:

In the end of November 2006, the language support provided by these virtual machine was still incomplete, and the build instructions recommended to use IBM's proprietary J9 instead to run the class library test suite. However, this is not necessary anymore (as of July 2007).

As for the rest of the project, DRLVM virtual machine development has now stalled (as of May 2011).[41]

Application status

Since its conception, Harmony grew in its ability to execute non-trivial Java applications.[42] As of July 2007, supported applications include:

However, Harmony's incomplete library prevented it from launching some other applications:

See also

References

  1. ↑ "The end of (Apache) Harmony". The H. November 4, 2011.
  2. ↑ "Original FAQ Questions from Project Launch". harmony.apache.org. Retrieved 2011-02-27. We are starting with Java SE 5, as that is the first version of Java SE for which the licensing allows an open source implementation, but we'll continue with Java SE 6 and any subsequent versions that follow.
  3. 1 2 "Class Library Component Status". harmony.apache.org. Retrieved 2011-02-27.
  4. 1 2 Amadeo, Ron (January 7, 2016). "Android N switches to OpenJDK, Google tells Oracle it is protected by the GPL". Ars Technica. Condé Nast. Retrieved July 1, 2016.
  5. 1 2 Ellison, Tim (2011-11-03). "Move Apache Harmony to the Attic (updated)". org.apache.harmony.dev. Archived from the original on 2011-11-03.
  6. 1 2 Ellison, Tim (2011-11-16). "Board accepted attic resolution". org.apache.harmony.dev. Archived from the original on 2011-11-16. Retrieved 2011-11-27.
  7. ↑ Mark Wielaard (2005-05-09). "Harmony!". Apache has set up a proposal for discussion around a full free j2se implementation. Which they call "Harmony". This is (at the moment) not about code, but about finding out a direction for getting to such a beast. Dalibor, Tom, Jeroen and I were asked to help them in that discussion and possibly show them how to set up a good architecture for it.
  8. ↑ Geir Magnusson Jr. (2006-05-24). "A proposal for a free Java implementation". Apache.
  9. 1 2 Mark Wielaard (2006-05-24). "Toward a free Java". LWN.net. All this means that, despite the fact that there is now some code available donated by Intel, there is no practical cooperation between the original free software projects backing Harmony and the project now known as Apache Harmony. All this made some people think of Harmony as a company consortium in the guise of an ASF project and not a full community project.
  10. ↑ "Open Letter to Sun Microsystems - JCK". apache.org.
  11. ↑ According to ASF, 1) a specification lead cannot impose any contractual condition or covenant that would limit or restrict the right of any licensee to create or distribute such Independent Implementations (section 5.C.III), and 2) a specification lead must license all necessary IP royalty-free to any compatible implementation of a specification (section 5.B).
  12. ↑ https://web.archive.org/web/20070421103127/http://blogs.sun.com/ontherecord/. Archived from the original on April 21, 2007. Missing or empty |title= (help)
  13. ↑ "Sun to Apache: "Open Source Process is a Journey" - Java IoT".
  14. ↑ "The Silence from an Open Sun". Ian Skerrett.
  15. ↑ "Mark J. Wielaard".
  16. ↑ Gilbert, Dave (2007-04-16). "Five Reasons Why Apache Will Regret That Open Letter". Retrieved 2008-03-08.
  17. ↑ "OpenJDK Community TCK License Agreement V 1.1" (PDF). Sun Microsystems. Retrieved 2008-03-08. Subject to and conditioned upon its Licensee Implementation being substantially derived from OpenJDK Code and, if such Implementation has or is to be distributed to a third party, its being distributed under the GPL License, Sun hereby grants to Licensee, to the extent of Sun's Intellectual Property Rights in the TCK, a worldwide, personal, non-exclusive, non-transferable, limited license to use the TCK internally and solely for the purpose of developing and testing Licensee Implementation.
  18. ↑ "The ASF Resigns From the JCP Executive Committee". Apache Software Foundation.
  19. ↑ "Apache quits Java governance group in protest of Oracle abuses". Ars Technica.
  20. ↑ "Google's Android SDK Bypasses Java ME in Favor of Java Lite and Apache Harmon". infoq.com. 2007-11-12. Retrieved 2009-05-31. Instead of providing a full version of the Java SE or Java ME Google has diverged on two fronts. First, a limited subset of the core Java packages is provided. (...) By going this route Android is following in the footsteps of another Google project GWT which uses Java as its development language but does not support the full JDK.
  21. ↑ "Package Index". Open Handset Alliance. Archived from the original on June 27, 2009. Retrieved 2009-05-31.
  22. ↑ "Oracle and IBM Collaborate to Accelerate Java Innovation Through OpenJDK". Oracle Corporation. Archived from the original on October 14, 2010. Retrieved 2010-10-22.
  23. ↑ Ryan Paul. "Java wars: IBM joins OpenJDK as Oracle shuns Apache Harmony". Ars Technica. Archived from the original on October 19, 2010. Retrieved 2010-10-22.
  24. ↑ Bob Sutor. "IBM joins the OpenJDK community, will help unify open source Java efforts". Archived from the original on October 18, 2010. Retrieved 2010-10-22. IBM will be shifting its development effort from the Apache Project Harmony to OpenJDK. For others who wish to do the same, we’ll work together to make the transition as easy as possible. IBM will still be vigorously involved in other Apache projects.
  25. ↑ Tim Ellison (2011-03-14). "Rebooting the Harmony project". Retrieved 2011-03-20.
  26. ↑ "What is the Future of Apache Harmony?". infoq.com. 2011-03-14. Retrieved 2011-03-20.
  27. ↑ "Mailing list archives: dev@harmony.apache.org". apache.org. Retrieved 2011-09-11.
  28. 1 2 "Board of Directors Meeting Minutes". Apache Software Foundation. November 16, 2011. Retrieved August 8, 2012. Larry wishes it to be noted that he is not against termination, he simply would have preferred to have more time to work on the messaging.
  29. ↑ Leo Simons (2006-07-24). "We would like all the development to happen right here".
  30. ↑ "The Apache Way".
  31. ↑ Harmony Documentation Team. "Apache Harmony - Supported Platforms". harmony.apache.org.
  32. ↑ "Results of comparison between JDK_5.0 and Harmony_5.0".
  33. ↑ http://cvs.savannah.gnu.org/viewcvs/*checkout*/classpath/org/omg/CORBA/ORB.java?rev=1.2.2.12&root=classpath
  34. ↑ http://cvs.savannah.gnu.org/viewcvs/*checkout*/classpath/gnu/CORBA/OrbFunctional.java?rev=1.6&root=classpath
  35. ↑ "Harmony uses latest Yoko jars...". September 27, 2006.
  36. ↑ http://svn.apache.org/repos/asf/incubator/yoko/trunk/yoko-spec-corba/src/main/java/org/omg/CORBA/ORB.java
  37. ↑ http://svn.apache.org/repos/asf/incubator/yoko/trunk/core/src/main/java/org/apache/yoko/orb/OBCORBA/ORB_impl.java
  38. ↑ "[general] JRockit H27.2.1 for Harmony Class Library released now".
  39. ↑ "Announcing Jikes RVM 3.0 + Apache Harmony!".
  40. ↑ "Janet Dev". Janet Dev.
  41. ↑ "Subversion Commits". harmony.apache.org. Retrieved 2011-05-28.
  42. ↑ "Application_Status". apache.org.
  43. ↑ http://wiki.apache.org/harmony/Eclipse_Unit_Tests_Pass_on_DRLVM#PassRate_2007
  44. ↑ "Apache_Tomcat". apache.org.
  45. ↑ "JUnit". apache.org.
  46. ↑ "Apache_Ant". apache.org.
  47. ↑ "Apache Harmony". apache.org.

External links

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