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 The Java Community Process (JCP), established in 1998, is a formalized mechanism that allows interested parties to develop standard technical specifications for Java technology. Anyone can become a JCP Member by filling a form available at thJCP w ...

, which are: *the JSR specification *the JSR

reference implementation In the software development process, a reference implementation (or, less frequently, sample implementation or model implementation) is a program that implements all requirements from a corresponding specification. The reference implementation o ...

*the Technology Compatibility Kit (TCK)

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 The Connected Limited Device Configuration (CLDC) is a specification of a framework for Java ME applications describing the basic set of libraries and virtual-machine features that must be present in an implementation. The CLDC is combined with one ...

mobile phones A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link while ...

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 Java is a set of computer software and specifications developed by James Gosling at Sun Microsystems, which was later acquired by the Oracle Corporation, that provides a system for developing application software and deploying it in a cro ...

is called Java Compatibility Kit (JCK). It is an extensive test suite used by

Oracle An oracle is a person or agency considered to provide wise and insightful counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. As such, it is a form of divination. Description The word ...

and licensees to ensure compatible implementations of the platform. The JCK for Java 6.0 source code has been released. The associated license did not initially allow users to compile or run the tests, but the right to see the code is not associated with tainting concerns, and public comments on the source code are allowed. However, since the release of

OpenJDK OpenJDK (Open Java Development Kit) is a free and open-source implementation of the Java Platform, Standard Edition (Java SE). It is the result of an effort Sun Microsystems began in 2006. The implementation is licensed under the GPL-2.0-only w ...

, a specific license allows running the JCK in the OpenJDK context, that is for any GPL implementation deriving substantially from OpenJDK. The OpenJDK Community TCK License Agreement v 2.0 has been published for the Java SE 7 Specification since December 2011.

TCK framework

The

JavaTest harness The JavaTest harness (or jtreg) is a regression tests framework specifically designed by Sun Microsystems to test the reference Java platform implementation. Although jtreg was originally designed to execute Technology Compatibility Kit (TCK) co ...

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 JUnit is a unit testing framework for the Java programming language. JUnit has been important in the development of test-driven development, and is one of a family of unit testing frameworks which is collectively known as xUnit that originated ...

TestNG TestNG is a testing framework for the Java programming language created by Cédric Beust and inspired by JUnit and NUnit. The design goal of TestNG is to cover a wider range of test categories: unit, functional, end-to-end, integration, etc., wit ...

License and controversy

Subsequent to Sun's release of

, Sun released a specific license to permit running the TCK in the OpenJDK context for any GPL implementation deriving substantially from OpenJDK. This requirement denies the

Apache Harmony 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 ...

project an Apache License-compatible right to use the TCK. On November 9, 2010, the

Apache Software Foundation The Apache Software Foundation (ASF) is an American nonprofit corporation (classified as a 501(c)(3) organization in the United States) to support a number of open source software projects. The ASF was formed from a group of developers of the ...

threatened to withdraw from the Java Community Process if they were not granted a TCK license for Harmony without additional restrictions. On December 9, 2010, the

resigned its seat on the Java SE/EE Executive Committee.The ASF Resigns From the JCP Executive Committee

blog, 2010-12-09

References

External links