From 160b6fd4966f5189f988eaf0f094867fb2155c04 Mon Sep 17 00:00:00 2001
From: Todd Lipcon <todd@apache.org>
Date: Wed, 26 Jan 2011 06:59:14 +0000
Subject: [PATCH] HADOOP-7118. Fix NPE in Configuration.writeXml. Contributed
 by Todd Lipcon

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1063613 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                           |  2 ++
 src/java/org/apache/hadoop/conf/Configuration.java    |  1 +
 .../org/apache/hadoop/conf/TestConfiguration.java     | 11 +++++++++++
 3 files changed, 14 insertions(+)

diff --git a/CHANGES.txt b/CHANGES.txt
index 74d4265a97..18504560f6 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -455,6 +455,8 @@ Release 0.22.0 - Unreleased
 
     HADOOP-7046. Fix Findbugs warning in Configuration. (Po Cheung via shv)
 
+    HADOOP-7118. Fix NPE in Configuration.writeXml (todd)
+
 Release 0.21.1 - Unreleased
 
   IMPROVEMENTS
diff --git a/src/java/org/apache/hadoop/conf/Configuration.java b/src/java/org/apache/hadoop/conf/Configuration.java
index 6b7df16694..c05acf3620 100644
--- a/src/java/org/apache/hadoop/conf/Configuration.java
+++ b/src/java/org/apache/hadoop/conf/Configuration.java
@@ -1620,6 +1620,7 @@ private synchronized Document asXmlDocument() throws IOException {
     Element conf = doc.createElement("configuration");
     doc.appendChild(conf);
     conf.appendChild(doc.createTextNode("\n"));
+    getProps(); // ensure properties is set
     for (Enumeration e = properties.keys(); e.hasMoreElements();) {
       String name = (String)e.nextElement();
       Object object = properties.get(name);
diff --git a/src/test/core/org/apache/hadoop/conf/TestConfiguration.java b/src/test/core/org/apache/hadoop/conf/TestConfiguration.java
index 52c887f308..fc9deef34f 100644
--- a/src/test/core/org/apache/hadoop/conf/TestConfiguration.java
+++ b/src/test/core/org/apache/hadoop/conf/TestConfiguration.java
@@ -18,6 +18,7 @@
 package org.apache.hadoop.conf;
 
 import java.io.BufferedWriter;
+import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileWriter;
 import java.io.IOException;
@@ -255,6 +256,16 @@ public void testToString() throws IOException {
     assertEquals(expectedOutput, conf.toString());
   }
   
+  public void testWriteXml() throws IOException {
+    Configuration conf = new Configuration();
+    ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
+    conf.writeXml(baos);
+    String result = baos.toString();
+    assertTrue("Result has proper header", result.startsWith(
+        "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?><configuration>"));
+    assertTrue("Result has proper footer", result.endsWith("</configuration>"));
+  }
+  
   public void testIncludes() throws Exception {
     tearDown();
     System.out.println("XXX testIncludes");