src/jdk.management/share/classes/com/sun/management/internal/VirtualThreadSchedulerImpls.java

*** 22,15 ***
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  package com.sun.management.internal;
  
- import java.util.concurrent.Executor;
  import java.util.concurrent.ForkJoinPool;
  import javax.management.ObjectName;
  import jdk.management.VirtualThreadSchedulerMXBean;
- import jdk.internal.access.JavaLangAccess;
  import jdk.internal.access.SharedSecrets;
  import jdk.internal.vm.ContinuationSupport;
  import sun.management.Util;
  
  /**
--- 22,13 ---

*** 88,61 ***
      private static final class VirtualThreadSchedulerImpl extends BaseVirtualThreadSchedulerImpl {
          /**
           * Holder class for scheduler.
           */
          private static class Scheduler {
!             private static final Executor scheduler =
!                 SharedSecrets.getJavaLangAccess().virtualThreadDefaultScheduler();
!             static Executor instance() {
!                 return scheduler;
              }
          }
  
          @Override
          public int getParallelism() {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  return pool.getParallelism();
              }
!             throw new InternalError();  // should not get here
          }
  
          @Override
          public void setParallelism(int size) {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  pool.setParallelism(size);
                  if (pool.getPoolSize() < size) {
                      // FJ worker thread creation is on-demand
                      Thread.startVirtualThread(() -> { });
                  }
- 
                  return;
              }
!             throw new UnsupportedOperationException();  // should not get here
          }
  
          @Override
          public int getPoolSize() {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  return pool.getPoolSize();
              }
!             return -1;  // should not get here
          }
  
          @Override
          public int getMountedVirtualThreadCount() {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  return pool.getActiveThreadCount();
              }
!             return -1;  // should not get here
          }
  
          @Override
          public long getQueuedVirtualThreadCount() {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  return pool.getQueuedTaskCount() + pool.getQueuedSubmissionCount();
              }
!             return -1L;  // should not get here
          }
      }
  
      /**
       * Implementation of VirtualThreadSchedulerMXBean when virtual threads are backed
--- 86,60 ---
      private static final class VirtualThreadSchedulerImpl extends BaseVirtualThreadSchedulerImpl {
          /**
           * Holder class for scheduler.
           */
          private static class Scheduler {
!             private static final Thread.VirtualThreadScheduler SCHEDULER =
!                 SharedSecrets.getJavaLangAccess().defaultVirtualThreadScheduler();
!             static Thread.VirtualThreadScheduler instance() {
!                 return SCHEDULER;
              }
          }
  
          @Override
          public int getParallelism() {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  return pool.getParallelism();
              }
!             return -1;  // unknown
          }
  
          @Override
          public void setParallelism(int size) {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  pool.setParallelism(size);
                  if (pool.getPoolSize() < size) {
                      // FJ worker thread creation is on-demand
                      Thread.startVirtualThread(() -> { });
                  }
                  return;
              }
!             throw new UnsupportedOperationException();
          }
  
          @Override
          public int getPoolSize() {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  return pool.getPoolSize();
              }
!             return -1;  // unknown
          }
  
          @Override
          public int getMountedVirtualThreadCount() {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  return pool.getActiveThreadCount();
              }
!             return -1;  // unknown
          }
  
          @Override
          public long getQueuedVirtualThreadCount() {
              if (Scheduler.instance() instanceof ForkJoinPool pool) {
                  return pool.getQueuedTaskCount() + pool.getQueuedSubmissionCount();
              }
!             return -1L;  // unknown
          }
      }
  
      /**
       * Implementation of VirtualThreadSchedulerMXBean when virtual threads are backed