From e71f61ecb87e04727a5a76e578a75714c9db6706 Mon Sep 17 00:00:00 2001
From: Jason Lowe <jlowe@apache.org>
Date: Tue, 18 Sep 2018 15:55:09 -0500
Subject: [PATCH] HADOOP-15755. StringUtils#createStartupShutdownMessage throws
 NPE when args is null. Contributed by Lokesh Jain and Dinesh Chitlangia

---
 .../main/java/org/apache/hadoop/util/StringUtils.java    | 2 +-
 .../java/org/apache/hadoop/util/TestStringUtils.java     | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/StringUtils.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/StringUtils.java
index 3db805fa4f..f49698ca5a 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/StringUtils.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/StringUtils.java
@@ -743,7 +743,7 @@ public static String createStartupShutdownMessage(String classname,
     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 "
diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestStringUtils.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestStringUtils.java
index 3fdc1bb8f8..f05b589567 100644
--- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestStringUtils.java
+++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestStringUtils.java
@@ -503,6 +503,15 @@ public void testEscapeHTML() {
         escapedStr, StringUtils.escapeHTML(htmlStr));
   }
 
+  @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";