https://issues.apache.org/jira/browse/AMQ-5336

URI comparison needs to be done using the host / port comparison method
instead of string equality due to other features like nested options
which can alter the URIs and lead to continued attempts to reconnect to
the transport that's already connected when priority backup is used.

activemq-client/src/main/java/org/apache/activemq/transport/failover/FailoverTransport.java

@@ -40,13 +40,12 @@ import java.util.concurrent.atomic.AtomicReference;
 import org.apache.activemq.broker.SslContext;
 import org.apache.activemq.command.Command;
 import org.apache.activemq.command.ConnectionControl;
-import org.apache.activemq.command.ConsumerControl;
 import org.apache.activemq.command.ConnectionId;
+import org.apache.activemq.command.ConsumerControl;
 import org.apache.activemq.command.MessageDispatch;
 import org.apache.activemq.command.MessagePull;
 import org.apache.activemq.command.RemoveInfo;
 import org.apache.activemq.command.Response;
-
 import org.apache.activemq.state.ConnectionStateTracker;
 import org.apache.activemq.state.Tracked;
 import org.apache.activemq.thread.Task;
@@ -270,7 +269,7 @@ public class FailoverTransport implements CompositeTransport {
                 if (canReconnect()) {
                     reconnectOk = true;
                 }
-                 LOG.warn("Transport (" + connectedTransportURI + ") failed"
+                LOG.warn("Transport (" + connectedTransportURI + ") failed"
                         + (reconnectOk ? "," : ", not") + " attempting to automatically reconnect", e);
 
                 failedConnectTransportURI = connectedTransportURI;
@@ -840,7 +839,6 @@ public class FailoverTransport implements CompositeTransport {
 
     @Override
     public <T> T narrow(Class<T> target) {
-
         if (target.isAssignableFrom(getClass())) {
             return target.cast(this);
         }
@@ -849,7 +847,6 @@ public class FailoverTransport implements CompositeTransport {
             return transport.narrow(target);
         }
         return null;
-
     }
 
     protected void restoreTransport(Transport t) throws Exception, IOException {
@@ -1167,7 +1164,7 @@ public class FailoverTransport implements CompositeTransport {
     }
 
     /*
-      * called with reconnectMutex held
+     * called with reconnectMutex held
      */
     private void propagateFailureToExceptionListener(Exception exception) {
         if (transportListener != null) {
@@ -1259,9 +1256,17 @@ public class FailoverTransport implements CompositeTransport {
         }
 
         if (!priorityList.isEmpty()) {
-            return priorityList.contains(uri);
+            for (URI priorityURI : priorityList) {
+                if (compareURIs(priorityURI, uri)) {
+                    return true;
+                }
+            }
+
+        } else if (!uris.isEmpty()) {
+            return compareURIs(uris.get(0), uri);
         }
-        return uris.indexOf(uri) == 0;
+
+        return false;
     }
 
     @Override
@@ -1370,6 +1375,10 @@ public class FailoverTransport implements CompositeTransport {
         return stateTracker;
     }
 
+    public boolean isConnectedToPriority() {
+        return connectedToPriority;
+    }
+
     private boolean contains(URI newURI) {
         boolean result = false;
         for (URI uri : uris) {
@@ -1468,5 +1477,4 @@ public class FailoverTransport implements CompositeTransport {
     public void setWarnAfterReconnectAttempts(int warnAfterReconnectAttempts) {
         this.warnAfterReconnectAttempts = warnAfterReconnectAttempts;
     }
-
 }

activemq-unit-tests/src/test/java/org/apache/activemq/bugs/AMQ5336Test.java

@@ -0,0 +1,77 @@
+/*
+ * 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.bugs;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import org.apache.activemq.ActiveMQConnection;
+import org.apache.activemq.ActiveMQConnectionFactory;
+import org.apache.activemq.broker.BrokerService;
+import org.apache.activemq.broker.TransportConnector;
+import org.apache.activemq.transport.failover.FailoverTransport;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Test for priority backup URI handling.
+ */
+public class AMQ5336Test {
+
+    private BrokerService brokerService;
+    private String connectionUri;
+
+    @Before
+    public void before() throws Exception {
+        brokerService = new BrokerService();
+        TransportConnector connector = brokerService.addConnector("tcp://localhost:0");
+        connectionUri = connector.getPublishableConnectString();
+        brokerService.setDeleteAllMessagesOnStartup(true);
+        brokerService.start();
+        brokerService.waitUntilStarted();
+    }
+
+    @After
+    public void after() throws Exception {
+        if (brokerService != null) {
+            brokerService.stop();
+            brokerService.waitUntilStopped();
+        }
+    }
+
+    @Test
+    public void test() throws Exception {
+        String uri = "failover:(" + connectionUri + ")" +
+                                "?randomize=false&" +
+                                "nested.socket.tcpNoDelay=true&" +
+                                "priorityBackup=true&" +
+                                "priorityURIs=" + connectionUri + "&" +
+                                "initialReconnectDelay=1000&" +
+                                "useExponentialBackOff=false";
+
+        ActiveMQConnectionFactory cf = new ActiveMQConnectionFactory(uri);
+        ActiveMQConnection connection = (ActiveMQConnection) cf.createConnection();
+        connection.start();
+
+        FailoverTransport failover = connection.getTransport().narrow(FailoverTransport.class);
+        assertNotNull(failover);
+        assertTrue(failover.isConnectedToPriority());
+
+        connection.close();
+    }
+}