HADOOP-15755. StringUtils#createStartupShutdownMessage throws NPE when args is null. Contributed by Lokesh Jain and Dinesh Chitlangia

(cherry picked from commit e71f61ecb8)

Conflicts:
	hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestStringUtils.java

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

@@ -743,7 +743,7 @@ public class StringUtils {
     return toStartupShutdownString("STARTUP_MSG: ", new String[] {
         "Starting " + classname,
         "  host = " + hostname,
-        "  args = " + Arrays.asList(args),
+        "  args = " + (args != null ? Arrays.asList(args) : new ArrayList<>()),
         "  version = " + VersionInfo.getVersion(),
         "  classpath = " + System.getProperty("java.class.path"),
         "  build = " + VersionInfo.getUrl() + " -r "

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestStringUtils.java

@@ -476,6 +476,15 @@ public class TestStringUtils extends UnitTestcaseTimeLimit {
     executorService.awaitTermination(50, TimeUnit.SECONDS);
   }
 
+  @Test
+  public void testCreateStartupShutdownMessage() {
+    //pass null args and method must still return a string beginning with
+    // "STARTUP_MSG"
+    String msg = StringUtils.createStartupShutdownMessage(
+        this.getClass().getName(), "test.host", null);
+    assertTrue(msg.startsWith("STARTUP_MSG:"));
+  }
+
   // Benchmark for StringUtils split
   public static void main(String []args) {
     final String TO_SPLIT = "foo,bar,baz,blah,blah";