Android Question again on MQTT library issue

[giggetto71]

Hi,
I am sorry to re-open this discussion but I keep receiving this error in the google developer still after 4 years. on my devices or emulator I never got one but for some reasons while in the field this issue is triggered.

Exception java.lang.NullPointerException: Attempt to invoke virtual method 'void org.eclipse.paho.client.mqttv3.internal.CommsTokenStore.quiesce(org.eclipse.paho.client.mqttv3.MqttException)' on a null object reference

Based on the below link to me it is crystal clear that they addressed this issue in the 1.2 version of their lib.

NPE when MqttAsyncClient is closed after unsuccessful connect · Issue #194 · eclipse-paho/paho.mqtt.java​

Steps to reproduce: Call MqttAsyncClient.connect() Immediately after IMqttActionListener.onFailure() is called, call MqttAsyncClient.close() Issue: MqttAsyncClient.connect() creates the shutdownCon...
github.com

The B4J version of this lib has been updated to 1.25 but apparently it's not possible for Android.
What can we do? there must be a way to update the existing library somehow PLEASE!

 

[Erel]

Can you post the full stack trace? Isn't it possible to catch this error?

 

[giggetto71]

Exception java.lang.NullPointerException: Attempt to invoke virtual method 'void org.eclipse.paho.client.mqttv3.internal.CommsTokenStore.quiesce(org.eclipse.paho.client.mqttv3.MqttException)' on a null object reference
at org.eclipse.paho.client.mqttv3.internal.ClientComms.shutdownConnection (ClientComms.java:310)
at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run (ClientComms.java:608)
at java.lang.Thread.run (Thread.java:1012)


the crash happens in the library so I cannot cath it.

 

[Erel]

It is problematic to update the library as the latest version isn't compatible with Android. Try to catch this error with Application_Error: https://www.b4x.com/android/forum/threads/uncaught-exceptions.59805/#content

 

[giggetto71]

I wiill try to explore Application_Error but I don't want to disrupt too much the published version. I believe the crash happens within a service within the app (not the starter, another service). should I use the application_error in that service or the starter service anyway? also I am bit reluctant to get rid of the crashes sent to google play as they are really useful.
In parallel would it be possible for Anywhere SW to evaluate another MQTT client lib? I mean long term I don' t believe remaining on a 10+ years old lib is a good idea anyway. I have see that there are other clients but maybe they are not easy to integrate? no idea.
thanks

 

[Erel]

In parallel would it be possible for Anywhere SW to evaluate another MQTT client lib?

That's definitely a good option. If you find a good candidate of such library then please post it.

Application_Error is only in the starter service and you can choose what to return from that sub based on the error. So only ignore this specific error.

 

[giggetto71]

how about

GitHub - hivemq/hivemq-mqtt-client: HiveMQ MQTT Client is an MQTT 5.0 and MQTT 3.1.1 compatible and feature-rich high-performance Java client library with different API flavours and backpressure support

HiveMQ MQTT Client is an MQTT 5.0 and MQTT 3.1.1 compatible and feature-rich high-performance Java client library with different API flavours and backpressure support - hivemq/hivemq-mqtt-client

github.com

it looks stable, maintained and very much supported by a large communiy.
not sure how complex it would be to integrate to B4A.

 

[Erel]

I checked this library and eventually decided to make paho compatible with Android: https://www.b4x.com/android/forum/threads/b4x-jmqtt-official-mqtt-client.59472/
It is possible to wrap this library however it has a large set of dependencies which makes it less attractive.

jMQTT v1.26 is based on paho v1.25 and is compatible with Android.

 

[giggetto71]

THANK YOU SOOOOOOOOO MUCH @Erel ! I will make some estensive tests and hopefully release it with my app soon! thanks again!

 

[bdunkleysmith]

Just for clarity @Erel, if I update from jMQTT v1.25 to v1.26, is

#PackagerProperty: AdditionalModuleInfoString = provides org.eclipse.paho.client.mqttv3.spi.NetworkModuleFactory with org.eclipse.paho.client.mqttv3.internal.TCPNetworkModuleFactory, org.eclipse.paho.client.mqttv3.internal.SSLNetworkModuleFactory,  org.eclipse.paho.client.mqttv3.internal.websocket.WebSocketNetworkModuleFactory, org.eclipse.paho.client.mqttv3.internal.websocket.WebSocketSecureNetworkModuleFactory;

no longer required if building a standalone package, presumably because you've included the modified org.eclipse.paho.client.mqttv3-1.2.5.jar in the zip.

 

[Erel]

You don't need these properties if using v1.26+. It is actually related to the modification I did in jMQTT.jar which changes the way the network modules are loaded, to make it compatible with both B4J and B4A.

 

[giggetto71]

I was reading the release notes of the paho java client and it's very very long list of improvements (most of them I don't even understand.. so I believe that having this lib up to date it's just great for the entire B4A community using MQTT as we all benefit from years of lib improvements! not to mention that security improvement and that since now we have the compatibility with Android we will stay up to date!

 

[giggetto71]

...and of curse i could not help to make a donation..

 

[byz]

hi @Erel I downloaded the latest jmqtt but it still shows 1.25 and my project is developed with b4j. And you should also add the following markup.

    #PackagerProperty: AdditionalModuleInfoString = provides org.eclipse.paho.client.mqttv3.spi.NetworkModuleFactory with org.eclipse.paho.client.mqttv3.internal.TCPNetworkModuleFactory, org.eclipse.paho.client.mqttv3.internal.SSLNetworkModuleFactory,  org.eclipse.paho.client.mqttv3.internal.websocket.WebSocketNetworkModuleFactory, org.eclipse.paho.client.mqttv3.internal.websocket.WebSocketSecureNetworkModuleFactory;

[B4X] jMQTT - Official MQTT client

Implementation of MQTT client based on the Paho open source project: http://www.eclipse.org/paho/ See this tutorial for more information: https://www.b4x.com/android/forum/threads/iot-mqtt-protocol.59471/ jMQTT v1.26 is compatible with B4J and B4A (older versions weren't compatible with B4A)...

www.b4x.com

 

[Erel]

jMQTT is an internal library in B4J (not in B4A) so you need to copy it to the internal libraries folder.