fix to address cycle bug with URL handlers

SHDP-92

Author: Costin Leau

src/main/java/org/springframework/data/hadoop/configuration/ConfigurationFactoryBean.java

@@ -23,6 +23,7 @@
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FsUrlStreamHandlerFactory;
+import org.apache.hadoop.security.UserGroupInformation;
 import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.InitializingBean;
@@ -67,6 +68,8 @@ public void afterPropertiesSet() throws Exception {
 
 		if (registerJvmUrl) {
 			try {
+				// force UGI init to prevent infinite loop - see SHDP-92
+				UserGroupInformation.setConfiguration(internalConfig);
 				URL.setURLStreamHandlerFactory(new FsUrlStreamHandlerFactory(getObject()));
 				log.info("Registered HDFS URL stream handler");
 			} catch (Error err) {

src/test/java/org/springframework/data/hadoop/configuration/UrlInfiniteLoopTest.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2011-2012 the original author or authors.
+ * 
+ * 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.
+ */
+package org.springframework.data.hadoop.configuration;
+
+import org.apache.hadoop.fs.FileSystem;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * See SHDP-92: https://jira.springsource.org/browse/SHDP-92
+ * @author Costin Leau
+ */
+public class UrlInfiniteLoopTest {
+
+	@Test
+	public void testInfiniteLoop() throws Exception {
+		ConfigurationFactoryBean factory = new ConfigurationFactoryBean();
+		factory.setRegisterUrlHandler(true);
+		factory.afterPropertiesSet();
+		assertNotNull(factory.getObject());
+		FileSystem fs = FileSystem.get(factory.getObject());
+		assertNotNull(fs);
+	}
+}