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

@@ -24,15 +24,18 @@
   */
  package jdk.internal.vm;
  
  import java.util.Arrays;
  import java.util.stream.Stream;
+ import jdk.internal.access.JavaLangAccess;
+ import jdk.internal.access.SharedSecrets;
  
  /**
   * Represents a snapshot of information about a Thread.
   */
- class ThreadSnapshot {
+ public class ThreadSnapshot {
+     private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
      private static final StackTraceElement[] EMPTY_STACK = new StackTraceElement[0];
      private static final ThreadLock[] EMPTY_LOCKS = new ThreadLock[0];
  
      // filled by VM
      private String name;

@@ -52,21 +55,23 @@
  
      private ThreadSnapshot() {}
  
      /**
       * Take a snapshot of a Thread to get all information about the thread.
-      * Return null if a ThreadSnapshot is not created, for example if the
-      * thread has terminated.
-      * @throws UnsupportedOperationException if not supported by VM
+      * @param thread the thread
+      * @param includeMonitors true to include the blocked on and owned object monitors
+      * @return the snapshot or {@code null} if the thread is not alive
       */
-     static ThreadSnapshot of(Thread thread) {
-         ThreadSnapshot snapshot = create(thread);
+     public static ThreadSnapshot of(Thread thread, boolean includeMonitors) {
+         ThreadSnapshot snapshot = create(thread, includeMonitors);
          if (snapshot == null) {
-             return null; // thread terminated
+             return null; // thread not alive
          }
          if (snapshot.stackTrace == null) {
              snapshot.stackTrace = EMPTY_STACK;
+         } else {
+             JLA.finishInit(snapshot.stackTrace);
          }
          if (snapshot.locks != null) {
              Arrays.stream(snapshot.locks).forEach(ThreadLock::finishInit);
          } else {
              snapshot.locks = EMPTY_LOCKS;

@@ -96,11 +101,11 @@
      }
  
      /**
       * Returns the thread stack trace.
       */
-     StackTraceElement[] stackTrace() {
+     public StackTraceElement[] stackTrace() {
          return stackTrace;
      }
  
      /**
       * Returns the thread's parkBlocker.

@@ -229,7 +234,7 @@
          ThreadBlocker(int typeOrdinal, Object obj, Thread owner) {
              this(lockTypeValues[typeOrdinal], obj, owner);
          }
      }
  
-     private static native ThreadSnapshot create(Thread thread);
+     private static native ThreadSnapshot create(Thread thread, boolean includeMonitors);
  }