Who should read it: It is for you if you are looking for a quick overview of this topic for a project, an interview, or in general.

What is the Technology Compatibility Kit (TCK): It is a suite of tests to check the compliance with Java Specification Request (JSR). It\’s also known as Java Compatibility Kit (JCK). This requires that all tests are implementation-independent. For a given platform to be considered \’conformant\’, all the TCK tests must pass and meet the testing requirements. 

Why TCK is important: TCK testing is important for below reasons:

• It ensures that the Java technology does not become fragmented.
• It helps developers to write code in a way that the solution is deployed to any platform, without any modifications.
• It allows developers to write the code compliant to Java technology rather than to a particular vendor\’s implementation.
• It allows application users to integrate their application to other applications with any environment.
  

Reference: 

• https://en.wikipedia.org/wiki/Technology_Compatibility_Kit
• https://jcp.org/en/resources/tdk
• https://docs.oracle.com/javame/test-tools/jctt/tck_project_planning_guide.pdf
• https://openjdk.java.net/groups/conformance/JckAccess/