HADOOP-9041. FsUrlStreamHandlerFactory could cause an infinite loop in FileSystem initialization. (Yanbo Liang and Radim Kolar via llu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1422435 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FsUrlStreamHandlerFactory.java

@@ -56,6 +56,12 @@ public class FsUrlStreamHandlerFactory implements
 
   public FsUrlStreamHandlerFactory(Configuration conf) {
     this.conf = new Configuration(conf);
+    // force init of FileSystem code to avoid HADOOP-9041
+    try {
+      FileSystem.getFileSystemClass("file", conf);
+    } catch (IOException io) {
+      throw new RuntimeException(io);
+    }
     this.handler = new FsUrlStreamHandler(this.conf);
   }
 

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFileSystemInitialization.java

@@ -0,0 +1,46 @@
+/**
+ * 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.fs;
+
+import org.apache.hadoop.conf.Configuration;
+
+import java.io.IOException;
+import java.net.URL;
+
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class TestFileSystemInitialization {
+
+ /**
+   * Check if FileSystem can be properly initialized if URLStreamHandlerFactory
+   * is registered.
+   */
+  @Test
+  public void testInitializationWithRegisteredStreamFactory() {
+    Configuration conf = new Configuration();
+    URL.setURLStreamHandlerFactory(new FsUrlStreamHandlerFactory(conf));
+    try {
+      FileSystem.getFileSystemClass("file", conf);
+    }
+    catch (IOException ok) {
+      // we might get an exception but this not related to infinite loop problem
+      assertFalse(false);
+    }
+  }
+}