HADOOP-11709. Time.NANOSECONDS_PER_MILLISECOND - use class-level final constant instead of method variable. Contributed by Ajith S.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -452,6 +452,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-11659. o.a.h.fs.FileSystem.Cache#remove should use a single hash map
     lookup. (Brahma Reddy Battula via aajisaka)
 
+    HADOOP-11709. Time.NANOSECONDS_PER_MILLISECOND - use class-level final
+    constant instead of method variable (Ajith S via ozawa)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/Time.java

@@ -27,6 +27,11 @@ import org.apache.hadoop.classification.InterfaceStability;
 @InterfaceStability.Unstable
 public final class Time {
 
+  /**
+   * number of nano seconds in 1 millisecond
+   */
+  private static final long NANOSECONDS_PER_MILLISECOND = 1000000;
+
   /**
    * Current system time.  Do not use this to calculate a duration or interval
    * to sleep, because it will be broken by settimeofday.  Instead, use
@@ -45,8 +50,6 @@ public final class Time {
    * @return a monotonic clock that counts in milliseconds.
    */
   public static long monotonicNow() {
-    final long NANOSECONDS_PER_MILLISECOND = 1000000;
-
     return System.nanoTime() / NANOSECONDS_PER_MILLISECOND;
   }
 }