https://issues.apache.org/jira/browse/AMQ-6476

Moving BrokerSubscriptionInfo processing into a new thread to prevent a
deadlock of the network bridge on startup

activemq-broker/src/main/java/org/apache/activemq/network/DemandForwardingBridgeSupport.java

@@ -163,6 +163,8 @@ public abstract class DemandForwardingBridgeSupport implements NetworkBridge, Br
     protected BrokerService brokerService = null;
     private ObjectName mbeanObjectName;
     private final ExecutorService serialExecutor = Executors.newSingleThreadExecutor();
+    //Use a new executor for processing BrokerSubscriptionInfo so we don't block other threads
+    private final ExecutorService syncExecutor = Executors.newSingleThreadExecutor();
     private Transport duplexInboundLocalBroker = null;
     private ProducerInfo duplexInboundLocalProducerInfo;
 
@@ -295,6 +297,14 @@ public abstract class DemandForwardingBridgeSupport implements NetworkBridge, Br
                                     List<Runnable> pendingTasks = serialExecutor.shutdownNow();
                                     LOG.info("pending tasks on stop {}", pendingTasks);
                                 }
+                                //Shutdown the syncExecutor, call countDown to make sure a thread can
+                                //terminate if it is waiting
+                                staticDestinationsLatch.countDown();
+                                syncExecutor.shutdown();
+                                if (!syncExecutor.awaitTermination(5, TimeUnit.SECONDS)) {
+                                    List<Runnable> pendingTasks = syncExecutor.shutdownNow();
+                                    LOG.info("pending tasks on stop {}", pendingTasks);
+                                }
                                 localBroker.oneway(new ShutdownInfo());
                                 remoteBroker.oneway(new ShutdownInfo());
                             } catch (Throwable e) {
@@ -648,10 +658,20 @@ public abstract class DemandForwardingBridgeSupport implements NetworkBridge, Br
                 } else if (command.isBrokerInfo()) {
                     futureRemoteBrokerInfo.set((BrokerInfo) command);
                 } else if (command instanceof BrokerSubscriptionInfo) {
+                    final BrokerSubscriptionInfo brokerSubscriptionInfo = (BrokerSubscriptionInfo) command;
+
+                    //Start in a new thread so we don't block the transport waiting for staticDestinations
+                    syncExecutor.execute(new Runnable() {
+
+                        @Override
+                        public void run() {
+                            try {
                                 staticDestinationsLatch.await();
-                    BrokerSubscriptionInfo subInfo = (BrokerSubscriptionInfo) command;
+                                //Make sure after the countDown of staticDestinationsLatch we aren't stopping
+                                if (!disposed.get()) {
+                                    BrokerSubscriptionInfo subInfo = brokerSubscriptionInfo;
                                     LOG.debug("Received Remote BrokerSubscriptionInfo on {} from {}",
-                            this.brokerService.getBrokerName(), subInfo.getBrokerName());
+                                            brokerService.getBrokerName(), subInfo.getBrokerName());
 
                                     if (configuration.isSyncDurableSubs() && configuration.isConduitSubscriptions()
                                             && !configuration.isDynamicOnly()) {
@@ -676,6 +696,14 @@ public abstract class DemandForwardingBridgeSupport implements NetworkBridge, Br
                                             }
                                         }
                                     }
+                                }
+                            } catch (Exception e) {
+                                LOG.warn("Error processing BrokerSubscriptionInfo: {}", e.getMessage(), e);
+                                LOG.debug(e.getMessage(), e);
+                            }
+                        }
+                    });
+
                 } else if (command.getClass() == ConnectionError.class) {
                     ConnectionError ce = (ConnectionError) command;
                     serviceRemoteException(ce.getException());