src/java.base/share/classes/java/lang/System.java

@@ -52,11 +52,10 @@
  import java.util.Map;
  import java.util.Objects;
  import java.util.Properties;
  import java.util.ResourceBundle;
  import java.util.Set;
- import java.util.concurrent.Executor;
  import java.util.function.Supplier;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.stream.Stream;
  
  import jdk.internal.javac.Restricted;

@@ -2321,14 +2320,26 @@
                  } else {
                      throw new IllegalArgumentException();
                  }
              }
  
-             public Executor virtualThreadDefaultScheduler() {
+             public Thread.VirtualThreadScheduler builtinVirtualThreadScheduler() {
+                 return VirtualThread.builtinScheduler(true);
+             }
+ 
+             public Thread.VirtualThreadScheduler defaultVirtualThreadScheduler() {
                  return VirtualThread.defaultScheduler();
              }
  
+             public Thread.VirtualThreadScheduler virtualThreadScheduler(Thread thread) {
+                 if (thread instanceof VirtualThread vthread) {
+                     return vthread.scheduler(true);
+                 } else {
+                     throw new IllegalArgumentException();
+                 }
+             }
+ 
              public StackWalker newStackWalkerInstance(Set<StackWalker.Option> options,
                                                        ContinuationScope contScope,
                                                        Continuation continuation) {
                  return StackWalker.newInstance(options, null, contScope, continuation);
              }