YARN-7266. Fixed deadlock in Timeline Server thread initialization.

Contributed by Prabhu Joseph

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/pom.xml

@@ -91,6 +91,12 @@
         </includes>
         <filtering>false</filtering>
       </resource>
+      <resource>
+        <directory>src/main/resources</directory>
+        <includes>
+          <include>**/jaxb.properties</include>
+        </includes>
+      </resource>
     </resources>
     <plugins>
       <plugin>

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/resources/org/apache/hadoop/yarn/api/records/timeline/jaxb.properties

@@ -0,0 +1,13 @@
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+javax.xml.bind.context.factory=org.apache.hadoop.yarn.server.applicationhistoryservice.webapp.ContextFactory

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/applicationhistoryservice/webapp/ContextFactory.java

@@ -0,0 +1,62 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.yarn.server.applicationhistoryservice.webapp;
+
+import java.util.Map;
+import java.lang.reflect.Method;
+import javax.xml.bind.JAXBContext;
+
+/**
+ * ContextFactory to reuse JAXBContextImpl for DAO Classes.
+ */
+public final class ContextFactory {
+
+  private static JAXBContext jaxbContext;
+
+  private ContextFactory() {
+  }
+
+  // Called from WebComponent.service
+  public static JAXBContext createContext(Class[] classes,
+      Map<String, Object> properties) throws Exception {
+    synchronized (ContextFactory.class) {
+      if (jaxbContext == null) {
+        Class spFactory = Class.forName(
+            "com.sun.xml.internal.bind.v2.ContextFactory");
+        Method m = spFactory.getMethod("createContext", Class[].class,
+            Map.class);
+        jaxbContext = (JAXBContext) m.invoke((Object) null, classes,
+            properties);
+      }
+    }
+    return jaxbContext;
+  }
+
+  // Called from WebComponent.init
+  public static JAXBContext createContext(String contextPath, ClassLoader
+      classLoader, Map<String, Object> properties) throws Exception {
+    Class spFactory = Class.forName(
+        "com.sun.xml.internal.bind.v2.ContextFactory");
+    Method m = spFactory.getMethod("createContext", String.class,
+        ClassLoader.class, Map.class);
+    return (JAXBContext) m.invoke(null, contextPath, classLoader,
+        properties);
+  }
+
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/test/java/org/apache/hadoop/yarn/server/applicationhistoryservice/webapp/TestAHSWebServices.java

@@ -28,12 +28,14 @@
 import java.net.URL;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 import java.util.Properties;
 
 import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletResponse;
+import javax.xml.bind.JAXBContext;
 import javax.ws.rs.core.MediaType;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.hadoop.conf.Configuration;
@@ -949,6 +951,15 @@ public void testContainerLogsMetaForFinishedApps() throws Exception {
         String.valueOf(content.length()));
   }
 
+  @Test
+  public void testContextFactory() throws Exception {
+    JAXBContext jaxbContext1 = ContextFactory.createContext(
+        new Class[]{}, Collections.EMPTY_MAP);
+    JAXBContext jaxbContext2 = ContextFactory.createContext(
+        new Class[]{}, Collections.EMPTY_MAP);
+    assertEquals(jaxbContext1, jaxbContext2);
+  }
+
   private static String getRedirectURL(String url) {
     String redirectUrl = null;
     try {