jdk/src/java.base/share/classes/sun/misc/VM.java

*** 1,7 ****
  /*
!  * Copyright (c) 1996, 2013, 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
--- 1,7 ----
  /*
!  * Copyright (c) 1996, 2015, 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
*** 400,409 ****
--- 400,439 ----
       * Returns the effective group ID of the calling process,
       * or -1 if the value is not available.
       */
      public static native long getegid();
  
+     /**
+      * Get a nanosecond time stamp adjustment in the form of a single long.
+      *
+      * This value can be used to create an instant using
+      * {@link java.time.Instant#ofEpochSecond(long, long)
+      *  java.time.Instant.ofEpochSecond(offsetInSeconds,
+      *  getNanoTimeAdjustment(offsetInSeconds))}.
+      * <p>
+      * The value returned has the best resolution available to the JVM on
+      * the current system.
+      * This is usually down to microseconds - or tenth of microseconds -
+      * depending on the OS/Hardware and the JVM implementation.
+      *
+      * @param offsetInSeconds The offset in seconds from which the nanosecond
+      *        time stamp should be computed.
+      *
+      * @apiNote The offset should be recent enough - so that
+      *         {@code offsetInSeconds} is within {@code +/- 2^32} seconds of the
+      *         current UTC time. If the offset is too far off, {@code -1} will be
+      *         returned. As such, {@code -1} must not be considered as a valid
+      *         nano time adjustment, but as an exception value indicating
+      *         that an offset closer to the current time should be used.
+      *
+      * @return A nanosecond time stamp adjustment in the form of a single long.
+      *     If the offset is too far off the current time, this method returns -1.
+      *     In that case, the caller should call this method again, passing a
+      *     more accurate offset.
+      */
+     public static native long getNanoTimeAdjustment(long offsetInSeconds);
+ 
      static {
          initialize();
      }
      private native static void initialize();
  }