src/java.base/share/classes/jdk/internal/vm/ThreadContainer.java

@@ -1,7 +1,7 @@
  /*
-  * Copyright (c) 2021, 2023, Oracle and/or its affiliates. All rights reserved.
+  * Copyright (c) 2021, 2025, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this

@@ -74,28 +74,51 @@
       * Returns a stream of the live threads in this container.
       */
      public abstract Stream<Thread> threads();
  
      /**
-      * Invoked by Thread::start before the given Thread is started.
+      * Invoked by {@code add} to add a thread to this container before it starts.
       */
-     public void onStart(Thread thread) {
-         // do nothing
+     protected void onStart(Thread thread) {
      }
  
      /**
-      * Invoked when a Thread terminates or starting it fails.
-      *
-      * For a platform thread, this method is invoked by the thread itself when it
-      * terminates. For a virtual thread, this method is invoked on its carrier
-      * after the virtual thread has terminated.
-      *
-      * If starting the Thread failed then this method is invoked on the thread
-      * that invoked onStart.
+      * Invoked by {@code remove} to remove a thread from this container when it
+      * terminates (or failed to start).
       */
-     public void onExit(Thread thread) {
-         // do nothing
+     protected void onExit(Thread thread) {
+     }
+ 
+     /**
+      * Adds a thread to this container. This method should be invoked before the
+      * thread executes.
+      */
+     public final void add(Thread thread) {
+         // Prevent a virtual thread from being preempted as this could potentially
+         // deadlock with a carrier is removing a virtual thread from the container
+         boolean pinned = ContinuationSupport.pinIfSupported();
+         try {
+             onStart(thread);
+         } finally {
+             if (pinned) Continuation.unpin();
+         }
+     }
+ 
+     /**
+      * Remove a thread from this container. This method can be invoked by the thread
+      * itself as it terminates, or it can be invoked by another thread after the given
+      * thread has terminated (or failed to start).
+      */
+     public final void remove(Thread thread) {
+         // Prevent a virtual thread from being preempted as this could potentially
+         // deadlock with a carrier is removing a virtual thread from the container
+         boolean pinned = ContinuationSupport.pinIfSupported();
+         try {
+             onExit(thread);
+         } finally {
+             if (pinned) Continuation.unpin();
+         }
      }
  
      /**
       * The scoped values captured when the thread container was created.
       */