Avoiding possible deadlock after Proton deliveries

activemq-protocols/activemq-amqp-protocol/src/main/java/org/apache/activemq/core/protocol/proton/ActiveMQProtonRemotingConnection.java

@@ -44,6 +44,11 @@ public class ActiveMQProtonRemotingConnection extends AbstractRemotingConnection
       this.amqpConnection = amqpConnection;
    }
 
+   public Executor getExecutor()
+   {
+      return this.executor;
+   }
+
    public ProtonProtocolManager getManager()
    {
       return manager;

activemq-protocols/activemq-amqp-protocol/src/main/java/org/apache/activemq/core/protocol/proton/plug/ActiveMQProtonConnectionCallback.java

@@ -16,6 +16,7 @@
  */
 package org.apache.activemq.core.protocol.proton.plug;
 
+import java.util.concurrent.Executor;
 import java.util.concurrent.TimeUnit;
 
 import io.netty.buffer.ByteBuf;
@@ -63,6 +64,18 @@ public class ActiveMQProtonConnectionCallback implements AMQPConnectionCallback
 
    }
 
+   public Executor getExeuctor()
+   {
+      if (protonConnectionDelegate != null)
+      {
+         return protonConnectionDelegate.getExecutor();
+      }
+      else
+      {
+         return null;
+      }
+   }
+
    @Override
    public void setConnection(AMQPConnectionContext connection)
    {

activemq-protocols/activemq-amqp-protocol/src/main/java/org/apache/activemq/core/protocol/proton/plug/ProtonSessionIntegrationCallback.java

@@ -17,6 +17,8 @@
 package org.apache.activemq.core.protocol.proton.plug;
 
 
+import java.util.concurrent.Executor;
+
 import io.netty.buffer.ByteBuf;
 import org.apache.qpid.proton.amqp.Binary;
 import org.apache.qpid.proton.amqp.transport.AmqpError;
@@ -172,10 +174,38 @@ public class ProtonSessionIntegrationCallback implements AMQPSessionCallback, Se
    }
 
    @Override
-   public void closeSender(Object brokerConsumer) throws Exception
+   public void closeSender(final Object brokerConsumer) throws Exception
+   {
+      Runnable runnable = new Runnable()
+      {
+         @Override
+         public void run()
+         {
+            try
             {
                ((ServerConsumer) brokerConsumer).close(false);
             }
+            catch (Exception e)
+            {
+            }
+         }
+      };
+
+
+      // Due to the nature of proton this could be happening within flushes from the queue-delivery (depending on how it happened on the protocol)
+      // to avoid deadlocks the close has to be done outside of the main thread on an executor
+      // otherwise you could get a deadlock
+      Executor executor = protonSPI.getExeuctor();
+
+      if (executor != null)
+      {
+         executor.execute(runnable);
+      }
+      else
+      {
+         runnable.run();
+      }
+   }
 
    @Override
    public ProtonJMessage encodeMessage(Object message, int deliveryCount) throws Exception