1.5. What are the JDK regression extensions to the JavaTest harness? What is "regtest"?

For the harness to execute tests in a given test suite, it needs specialized code which knows how to find test descriptions and how to interpret those descriptions. The JDK Test Framework: Tag Language Specification provides the needed descriptions. regtest refers to extensions for the JavaTest harness that implement this specification, and is an older name for what is now known as "jtreg".