Technology Compatibility Kit

Last updated

A Technology Compatibility Kit (TCK) is a suite of tests that at least nominally checks a particular alleged implementation of a Java Specification Request (JSR) for compliance. It is one of the three required pieces for a ratified JSR in the Java Community Process, which are:

Contents

Contents and architecture

TCKs tend to be obtained from the Specification Lead of a given JSR. They usually (but not always) consist of a graphical host application which communicates over TCP/IP with the device or Java virtual machine that is under test. Tests are typically obtained by the device over HTTP, and results are posted back to the host application in a similar way. This decoupling enables TCKs to be used to test virtual machines on devices such as CLDC mobile phones which do not have the power to run the full TCK host application.

The tests contained in the JSR are supposedly derived from the statements in the JSR specification. Any given API will have a set of tests to ensure that it behaves in the intended way, including in error conditions.

In order to state conformance with a given JSR, a Java implementation has to pass the associated TCK. Any (rare) exceptions have to be negotiated with the specification lead. Because of this, TCKs are of great importance when implementing a JSR. The first great milestone is to get the TCK running in the first place, which necessarily involves the Java implementation and underlying networking stack having a certain level of maturity. Next, the TCK must be properly configured - because they must be flexible enough to cope with any implementation, there are many options. (For example, listing all the supported media formats and associated optional controls for JSR135). Particular tests also require some setup activity - this tends to be particularly complex for the tests which ensure correct behaviour in error conditions, because the Java implementation must be put in the right state to cause each error. Finally, each failing test must be fixed, which is usually handled by the usual defect tracking mechanisms.

Some Java implementors consider their product to be mainly complete once the TCKs pass. Whilst it's true that the TCKs are quite comprehensive, there are many areas that they do not cover. These include performance, as well as the optional features. There's no alternative but to do much real-world testing to address these shortcomings, although additional test suites such as JDTS may help.

TCK for the Java platform

The Technology Compatibility Kit for a particular Java platform is called Java Compatibility Kit (JCK). It is an extensive test suite used by Oracle and licensees to ensure compatible implementations of the platform.

The JCK for Java 6.0 source code has been released. [1] [2] The associated license did not initially allow users to compile or run the tests, [3] but the right to see the code is not associated with tainting concerns, and public comments on the source code are allowed. [1] However, since the release of OpenJDK, a specific license allows running the JCK in the OpenJDK context, that is for any GPL implementation deriving substantially from OpenJDK. [4] [5]

The OpenJDK Community TCK License Agreement v 2.0 has been published for the Java SE 7 Specification since December 2011. [6]

TCK framework

The JavaTest harness tool is today the most common unit testing framework used to verify the implementation compliance. It is a general purpose testing framework designed to run TCK tests. However, some specifications are also using JUnit or TestNG. [7]

License and controversy

Subsequent to Sun's release of OpenJDK, Sun released a specific license to permit running the TCK in the OpenJDK context for any GPL implementation deriving substantially from OpenJDK. [8]

This requirement denies the Apache Harmony project an Apache License-compatible right to use the TCK. On November 9, 2010, the Apache Software Foundation threatened to withdraw from the Java Community Process if they were not granted a TCK license for Harmony without additional restrictions. [9]

On December 9, 2010, the Apache Software Foundation resigned its seat on the Java SE/EE Executive Committee. [10]

See also

Related Research Articles

<span class="mw-page-title-main">Java virtual machine</span> Virtual machine that runs Java programs

A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally describes what is required in a JVM implementation. Having a specification ensures interoperability of Java programs across different implementations so that program authors using the Java Development Kit (JDK) need not worry about idiosyncrasies of the underlying hardware platform.

The Java Community Process (JCP), established in 1998, is a formal mechanism that enables interested parties to develop standard technical specifications for Java technology. Becoming a member of the JCP requires solid knowledge of the Java programming language, its specifications, and best practices in software development. Membership in the JCP involves a detailed review of the candidate's profile, including an assessment by current members. Typically, professionals are invited to join the JCP based on their contributions and reputation within the Java community.

<span class="mw-page-title-main">GNU Classpath</span> Implementation of standard class library of Java

GNU Classpath is a free software implementation of the standard class library for the Java programming language. Most classes from J2SE 1.4 and 5.0 are implemented. Classpath can thus be used to run Java-based applications. GNU Classpath is a part of the GNU Project. It was originally developed in parallel with libgcj due to license incompatibilities, but later the two projects merged.

Free Java implementations are software projects that implement Oracle's Java technologies and are distributed under free software licences, making them free software. Sun released most of its Java source code as free software in May 2007, so it can now almost be considered a free Java implementation. Java implementations include compilers, runtimes, class libraries, etc. Advocates of free and open source software refer to free or open source Java virtual machine software as free runtimes or free Java runtimes.

javac is the primary Java compiler included in the Java Development Kit (JDK) from Oracle Corporation. Martin Odersky implemented the GJ compiler, and his implementation became the basis for javac.

HotSpot, released as Java HotSpot Performance Engine, is a Java virtual machine for desktop and server computers, developed by Sun Microsystems which was purchased by and became a division of Oracle Corporation in 2010. Its features improved performance via methods such as just-in-time compilation and adaptive optimization. It is the de facto Java Virtual Machine, serving as the reference implementation of the Java programming language.

Apache Harmony is a retired open source, free Java implementation, developed by the Apache Software Foundation. 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 99% completeness for J2SE 5.0, and 97% for Java SE 6. The Android operating system has historically been a major user of Harmony, although since Android Nougat it increasingly relies on OpenJDK libraries.

Java APIs for Bluetooth Wireless Technology (JABWT) is a J2ME specification for APIs that allows Java MIDlets running on embedded devices such as mobile phones to use Bluetooth for short-range wireless communication. JABWT was developed as JSR-82 under the Java Community Process.

<span class="mw-page-title-main">GlassFish</span> Application server project

GlassFish is an open-source Jakarta EE platform application server project started by Sun Microsystems, then sponsored by Oracle Corporation, and now living at the Eclipse Foundation and supported by OmniFish, Fujitsu and Payara. The supported version under Oracle was called Oracle GlassFish Server. GlassFish is free software and was initially dual-licensed under two free software licences: the Common Development and Distribution License (CDDL) and the GNU General Public License (GPL) with the Classpath exception. After having been transferred to Eclipse, GlassFish remained dual-licensed, but the CDDL license was replaced by the Eclipse Public License (EPL).

<span class="mw-page-title-main">Java (software platform)</span> Set of computer software and specifications

Java is a set of computer software and specifications that provides a software platform for developing application software and deploying it in a cross-platform computing environment. Java is used in a wide variety of computing platforms from embedded devices and mobile phones to enterprise servers and supercomputers. Java applets, which are less common than standalone Java applications, were commonly run in secure, sandboxed environments to provide many features of native applications through being embedded in HTML pages.

<span class="mw-page-title-main">Apache MyFaces</span> Open-source implementation of JavaServer Faces

Apache MyFaces is an Apache Software Foundation project that creates and maintains an open-source JavaServer Faces implementation, along with several libraries of JSF components that can be deployed on the core implementation. The project is divided into several sub-projects:

The Java language has undergone several changes since JDK 1.0 as well as numerous additions of classes and packages to the standard library. Since J2SE 1.4, the evolution of the Java language has been governed by the Java Community Process (JCP), which uses Java Specification Requests (JSRs) to propose and specify additions and changes to the Java platform. The language is specified by the Java Language Specification (JLS); changes to the JLS are managed under JSR 901. In September 2017, Mark Reinhold, chief Architect of the Java Platform, proposed to change the release train to "one feature release every six months" rather than the then-current two-year schedule. This proposal took effect for all following versions, and is still the current release schedule.

OpenJDK is a free and open-source implementation of the Java Platform, Standard Edition. It is the result of an effort Sun Microsystems began in 2006. The implementation is licensed under the GNU General Public License 2 with a linking exception, preventing components that linked to the Java Class Library becoming subject to the terms of the GPL license. OpenJDK is the official reference implementation of Java SE since version 7, and is the most popular distribution of the JDK.

OpenJPA is an open source implementation of the Java Persistence API specification. It is an object-relational mapping (ORM) solution for the Java language, which simplifies storing objects in databases. It is open-source software distributed under the Apache License 2.0.

The Java Class Library (JCL) is a set of dynamically loadable libraries that Java Virtual Machine (JVM) languages can call at run time. Because the Java Platform is not dependent on a specific operating system, applications cannot rely on any of the platform-native libraries. Instead, the Java Platform provides a comprehensive set of standard class libraries, containing the functions common to modern operating systems.

IcedTea is a build and integration project for OpenJDK launched by Red Hat in June 2007. IcedTea also includes some addon libraries: IcedTea-Web is a free software implementation of Java Web Start and the Java web browser applet plugin. IcedTea-Sound is a collection of plugins for the Java sound subsystem, including the PulseAudio provider which used to be included with IcedTea. The Free Software Foundation recommends that all Java programmers use IcedTea as their development environment.

The Java Development Kit (JDK) is a distribution of Java technology by Oracle Corporation. It implements the Java Language Specification (JLS) and the Java Virtual Machine Specification (JVMS) and provides the Standard Edition (SE) of the Java Application Programming Interface (API). It is derivative of the community driven OpenJDK which Oracle stewards. It provides software for working with Java applications. Examples of included software are the Java virtual machine, a compiler, performance monitoring tools, a debugger, and other utilities that Oracle considers useful for Java programmers.

The JavaTest harness is a regression tests framework specifically designed by Sun Microsystems to test the reference Java platform implementation.

Google LLC v. Oracle America, Inc., 593 U.S. ___ (2021), was a U.S. Supreme Court decision related to the nature of computer code and copyright law. The dispute centered on the use of parts of the Java programming language's application programming interfaces (APIs) and about 11,000 lines of source code, which are owned by Oracle, within early versions of the Android operating system by Google. Google has since transitioned Android to a copyright-unburdened engine without the source code, and has admitted to using the APIs but claimed this was within fair use.

References

  1. 1 2 Hamilton, Graham (2004-12-13). "J2SE Compatibility Test Sources Released". Archived from the original on 2004-12-16. Retrieved 2008-03-08. We have tried to make sure the license meets the reasonable needs of developers who want to evaluate the JCK sources: It's available at zero cost, through a click-through license; There is no "tainting". Once you delete your copy of the JCK, you aren't constrained in your future actions. To try to make this really clear, we included a section explicitly granting what the lawyers call "residual rights", which basically means that stuff that sticks in your head is OK to use in the future; You can publish feedback and comments publicly.
  2. ↑ JCK project Archived July 8, 2007, at the Wayback Machine
  3. ↑ ""READ ONLY" SOURCE LICENSE AGREEMENT, v1.0 JAVA (TM) COMPATIBILITY KIT 6a". Sun Microsystems. June 2007. Archived from the original on 2010-12-31. Retrieved 2008-03-08.
  4. ↑ Darcy, Joseph (2008-03-06). "Matching JDK and JCK Versions". Archived from the original on 2011-08-12. Retrieved 2008-03-08. If you're interested in running the JCK in context of OpenJDK projects, a license is available.
  5. ↑ "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.
  6. ↑ "OpenJDK Community TCK license agreement V 2.0" (PDF). openjdk.java.net.
  7. ↑ "Source Code Browse: jsr-352-git-repository". Archived from the original on 2013-03-05. Retrieved 2014-02-12.
  8. ↑ "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.
  9. ↑ Statement by the ASF Board on our participation in the Java Community Process, Apache Software Foundation blog, 2010-11-09
  10. ↑ The ASF Resigns From the JCP Executive Committee, Apache Software Foundation blog, 2010-12-09
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.