diff --git a/artemis-jms-client/src/main/java/org/apache/activemq/artemis/jndi/LazyCreateContext.java b/artemis-jms-client/src/main/java/org/apache/activemq/artemis/jndi/LazyCreateContext.java index 52269d3dca..5b1a6262b9 100644 --- a/artemis-jms-client/src/main/java/org/apache/activemq/artemis/jndi/LazyCreateContext.java +++ b/artemis-jms-client/src/main/java/org/apache/activemq/artemis/jndi/LazyCreateContext.java @@ -23,15 +23,22 @@ public abstract class LazyCreateContext extends ReadOnlyContext { @Override public Object lookup(String name) throws NamingException { - try { - return super.lookup(name); - } catch (NameNotFoundException e) { - Object answer = createEntry(name); - if (answer == null) { - throw e; + /* + * The lookup and the internalBind should be performed atomically to avoid + * race conditions between multiple threads where the lookup fails for both + * threads initially then the internalBind fails for the second thread. + */ + synchronized (this) { + try { + return super.lookup(name); + } catch (NameNotFoundException e) { + Object answer = createEntry(name); + if (answer == null) { + throw e; + } + internalBind(name, answer); + return answer; } - internalBind(name, answer); - return answer; } } diff --git a/artemis-jms-client/src/test/java/org/apache/activemq/artemis/jndi/JndiTest.java b/artemis-jms-client/src/test/java/org/apache/activemq/artemis/jndi/JndiTest.java new file mode 100644 index 0000000000..ad20245607 --- /dev/null +++ b/artemis-jms-client/src/test/java/org/apache/activemq/artemis/jndi/JndiTest.java @@ -0,0 +1,78 @@ +/* + * 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.activemq.artemis.jndi; + +import javax.naming.Context; +import javax.naming.InitialContext; +import java.util.Hashtable; +import java.util.UUID; + +import org.junit.Assert; +import org.junit.Test; + +import static org.apache.activemq.artemis.jndi.ActiveMQInitialContextFactory.DYNAMIC_QUEUE_CONTEXT; + +public class JndiTest { + + @Test + public void testMultiThreadedDynamicQueueLookup() throws Exception { + final int nThreads = 10; + + LookerUpper[] lookerUppers = new LookerUpper[nThreads]; + for (int j = 0; j < 100; j++) { + Hashtable props = new Hashtable<>(); + props.put(Context.INITIAL_CONTEXT_FACTORY, "org.apache.activemq.artemis.jndi.ActiveMQInitialContextFactory"); + InitialContext context = new InitialContext(props); + String lookup = DYNAMIC_QUEUE_CONTEXT + "/" + UUID.randomUUID().toString(); + + for (int i = 0; i < nThreads; i++) { + lookerUppers[i] = new LookerUpper(context, lookup); + } + + for (int i = 0; i < nThreads; i++) { + lookerUppers[i].start(); + } + + for (LookerUpper lookerUpper : lookerUppers) { + lookerUpper.join(); + Assert.assertFalse(lookerUpper.failed); + } + context.close(); + } + } + + class LookerUpper extends Thread { + InitialContext context; + String lookup; + boolean failed = false; + + LookerUpper(InitialContext context, String lookup) throws Exception { + this.context = context; + this.lookup = lookup; + } + + @Override + public void run() { + try { + context.lookup(lookup); + } catch (Throwable e) { + failed = true; + } + } + } +}