HADOOP-16265. Fix bug causing Configuration#getTimeDuration to use incorrect units when the default value is used. Contributed by starphin.

(cherry-picked from 1ddb48872f6a4985f4d0baadbb183899226cff68)
(cherry-picked from 28ff96f367ab2260666c2177980bce7c66e6dc57)
(cherry-picked from 9da70a1b4b7196492991fa2857314e5bbf57db28)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java

@@ -1773,7 +1773,7 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
       TimeUnit defaultUnit, TimeUnit returnUnit) {
     String vStr = get(name);
     if (null == vStr) {
-      return defaultValue;
+      return returnUnit.convert(defaultValue, defaultUnit);
     } else {
       return getTimeDurationHelper(name, vStr, defaultUnit, returnUnit);
     }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfiguration.java

@@ -1367,6 +1367,10 @@ public class TestConfiguration {
   @Test
   public void testTimeDuration() {
     Configuration conf = new Configuration(false);
+
+    assertEquals(7000L,
+        conf.getTimeDuration("test.time.a", 7L, SECONDS, MILLISECONDS));
+
     conf.setTimeDuration("test.time.a", 7L, SECONDS);
     assertEquals("7s", conf.get("test.time.a"));
     assertEquals(0L, conf.getTimeDuration("test.time.a", 30, MINUTES));