Unable to run MQTT script

Getting the following error when trying to run a MQTT protocol script. Can some one help me out

17:13:48.394 [ERROR] i.g.a.Gatling$ - Run crashed
java.lang.ClassNotFoundException: scala.Serializable
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
… 24 common frames omitted
Wrapped by: java.lang.NoClassDefFoundError: scala/Serializable
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
at java.lang.ClassLoader.loadClass(ClassLoader.java:411)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at com.github.mnogu.gatling.mqtt.test.MqttSimulation.(MqttSimulation.scala:10)
… 10 common frames omitted
Wrapped by: java.lang.reflect.InvocationTargetException: null
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at io.gatling.app.Runner.run0(Runner.scala:62)
at io.gatling.app.Runner.run(Runner.scala:49)
at io.gatling.app.Gatling$.start(Gatling.scala:83)
at io.gatling.app.Gatling$.fromArgs(Gatling.scala:45)
at io.gatling.app.Gatling$.main(Gatling.scala:37)
at io.gatling.app.Gatling.main(Gatling.scala)
Exception in thread “main” java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at io.gatling.app.Runner.run0(Runner.scala:62)
at io.gatling.app.Runner.run(Runner.scala:49)
at io.gatling.app.Gatling$.start(Gatling.scala:83)
at io.gatling.app.Gatling$.fromArgs(Gatling.scala:45)
at io.gatling.app.Gatling$.main(Gatling.scala:37)
at io.gatling.app.Gatling.main(Gatling.scala)
Caused by: java.lang.NoClassDefFoundError: scala/Serializable
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
at java.lang.ClassLoader.loadClass(ClassLoader.java:411)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at com.github.mnogu.gatling.mqtt.test.MqttSimulation.(MqttSimulation.scala:10)
… 10 more
Caused by: java.lang.ClassNotFoundException: scala.Serializable
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
… 24 more

You’re mixing different incompatible Scala versions, eg trying to use Gatling 3.6 (using Scala 2.13) and a third party plugin compiled against Scala 2.12.
You’ll have to either upgrade the plugin or downgrade Gatling.

I have tried to create the mqtt plugin using the latest version of scala & sbt but i couldn’t install. It is throwing error when i use the following command sudo dpkg -i scala. 2.13.6.deb

Gatling has an official MQTT support that’s only available for Gatling Enterprise customers.

If you’re using a third party MQTT plugin, it’s not supported here. If you have any issue with it, you have to reach out to its authors, typically on their GitHub project.