HADOOP-16749. Configuration parsing of CDATA values are blank

Signed-off-by: Jonathan Eagles <jeagles@gmail.com>
(cherry picked from commit c4fb43c94259546f2c96b50ceae9cd3adb726166)

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

@@ -3322,6 +3322,7 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
         handleStartElement();
         break;
       case XMLStreamConstants.CHARACTERS:
+      case XMLStreamConstants.CDATA:
         if (parseToken) {
           char[] text = reader.getTextCharacters();
           token.append(text, reader.getTextStart(), reader.getTextLength());

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

@@ -2553,4 +2553,41 @@ public class TestConfiguration {
     // Thread 1
     config.get("secondParse");
   }
+
+  @Test
+  public void testCDATA() throws IOException {
+    String xml = new String(
+        "<configuration>" +
+          "<property>" +
+            "<name>cdata</name>" +
+            "<value><![CDATA[>cdata]]></value>" +
+          "</property>\n" +
+          "<property>" +
+            "<name>cdata-multiple</name>" +
+            "<value><![CDATA[>cdata1]]> and <![CDATA[>cdata2]]></value>" +
+          "</property>\n" +
+          "<property>" +
+            "<name>cdata-multiline</name>" +
+            "<value><![CDATA[>cdata\nmultiline<>]]></value>" +
+          "</property>\n" +
+          "<property>" +
+            "<name>cdata-whitespace</name>" +
+            "<value>  prefix <![CDATA[>cdata]]>\nsuffix  </value>" +
+          "</property>\n" +
+        "</configuration>");
+    Configuration conf = checkCDATA(xml.getBytes());
+    ByteArrayOutputStream os = new ByteArrayOutputStream();
+    conf.writeXml(os);
+    checkCDATA(os.toByteArray());
+  }
+
+  private static Configuration checkCDATA(byte[] bytes) {
+    Configuration conf = new Configuration(false);
+    conf.addResource(new ByteArrayInputStream(bytes));
+    assertEquals(">cdata", conf.get("cdata"));
+    assertEquals(">cdata1 and >cdata2", conf.get("cdata-multiple"));
+    assertEquals(">cdata\nmultiline<>", conf.get("cdata-multiline"));
+    assertEquals("  prefix >cdata\nsuffix  ", conf.get("cdata-whitespace"));
+    return conf;
+  }
 }