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.