[paho-dev] Client hangs forever if trying to shut down when connection t

[nidhi.kushwaha@xxxxxxxxxxx]

Title: Default Disclaimer Daimler AG

Hi

 

I am using Paho(Java client) in auto re-connect mode. I am unable to properly shut down the client when connection to broker is lost.

Client hangs forever and java application does not terminate.

 

Code snippet -

private void runClient() throws MqttException, InterruptedException {

       ………… …………. …………. ………….

       ………… …………. …………. ………….

 

        // Connect to Broker

        final IMqttToken connect = gcdClient.connect( connOpt );

        connect.waitForCompletion();

 

        Thread.sleep( 10_000 );

        // SCENARIO - If connection to broker is lost at this point. May be broker is down or other reason.

 

        // Trying to shutdown the connection

        log.info( "Trying to shutdown the client" );

        try {

            gcdClient.disconnect().waitForCompletion();

        } catch ( MqttException ex ) {

            log.error( "Exception while disconnecting", ex );

        } finally {

            log.info( "Close the client" );

            gcdClient.close();

        }

 

    }

 

Attaching the java file. Here is the stack trace –

 

11:50:29.459 [main] INFO TestMqtt - Connecting to MQTT Broker

11:50:29.489 [MQTT Call: clientID123] INFO TestMqtt - connectComplete - MQTT Publisher connected to MQTT Broker : tcp://localhost:1883  reconnect=false

11:50:30.989 [MQTT Rec: clientID123] ERROR TestMqtt - connectionLost - MQTT Publisher disconnected from MQTT Broker

11:50:39.498 [main] INFO TestMqtt - Trying to shutdown the client

11:50:39.498 [main] ERROR TestMqtt - Exception while disconnecting

org.eclipse.paho.client.mqttv3.MqttException: Client is disconnected

               at org.eclipse.paho.client.mqttv3.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:31)

               at org.eclipse.paho.client.mqttv3.internal.ClientComms.disconnect(ClientComms.java:451)

               at org.eclipse.paho.client.mqttv3.MqttAsyncClient.disconnect(MqttAsyncClient.java:632)

               at org.eclipse.paho.client.mqttv3.MqttAsyncClient.disconnect(MqttAsyncClient.java:601)

               at org.eclipse.paho.client.mqttv3.MqttAsyncClient.disconnect(MqttAsyncClient.java:608)

               at TestMqtt.runClient(TestMqtt.java:47)

               at TestMqtt.main(TestMqtt.java:22)

11:50:39.498 [main] INFO TestMqtt - Close the client

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Attachment: TestMqtt.java
Description: TestMqtt.java