This Annex to the Java SE 21 Specification contains the Java SE 21 version of the JVM Tool Interface (JVM TI).

The Java SE 21 version includes corrections and clarifications made to the JVM TI since the Java SE 20 version, that is, since the Final Release of JSR 395. These changes are flagged with colorful text, as follows:

• Text with light green background indicates new material in the Java SE 21 version.
• Text struck through on a light red background indicates deletion from the Java SE 20 version.

Informative background for these changes may be found in the following approved Compatibility & Specification Review (CSR) requests:

• JEP 444 Virtual Threads
  Compatibility & Specification Review
• JEP 451 Prepare to Restrict the Dynamic Loading of Agents
  Compatibility & Specification Review
• Add ForceEarlyReturn support for virtual threads
  Compatibility & Specification Review
• Add PopFrame support for virtual threads
  Compatibility & Specification Review
• Add support of virtual threads to JVMTI StopThread
  Compatibility & Specification Review
• Clarify JVMTI heap functions spec about virtual thread stack
  Compatibility & Specification Review
• Extend SetLocalXXX minimal support for virtual threads
  Compatibility & Specification Review
• Get rid of compatibility ThreadStart/ThreadEnd events for virtual threads
  Compatibility & Specification Review
• GetCurrentThreadCpuTime and GetThreadCpuTime need further clarification for virtual threads
  Compatibility & Specification Review
• Make JVMTI thread cpu time functions optional for virtual threads
  Compatibility & Specification Review