scala-maven-plugin | previously maven-scala-plugin | Plugin library

If you have scala source code you need

• to add the scala-maven-plugin (please use a more recent version see https://search.maven.org/search?q=a:scala-maven-plugin, today 4.5.6 is the latest, why using 3.3.3 from 2018-06 ?) to compile your code
• to have the scala-library as an explicit dependency

And remove

Disclaimer: Gatling founder and scala-maven-plugin co-maintainer here

Annotation processing, in particular Lombok, is a super weird beast. It seems scala-maven-plugin doesn't support it, see https://github.com/davidB/scala-maven-plugin/issues/342 (was closed due to lack of activity/contribution).

Then, I recommend you isolate your Gatling tests in a dedicated module, so you can build your Lombok based test classes in a pure Java module that would publish a test jar and then have your Gatling module depend on this test-jar.

1. java is compiled first, if both compilation are run in their default phase
2. scala depends of java, nothing to customize, it's the default behavior. If java depends of scala you should force the compilation of scala code during a phase before like process-resources.
3. Yes you can have "mixed" scala/java, in this case scala compiler should run before and be aware of java source (the scala compiler will parse them to extract API). It's the same configuration than scala first

It seems you are using Spark 3.x with a jar that was compiled and includes spark 2.4.8 artifacts. The solution is simple: mark scala-library and spark-sql with the scope provided. Also, as you bring the spark-bigquery-connector externally, you don't need to add it to the code (as well as the google-cloud-* dependencies, unless you're using them directly)

You are using scalatest version 2.2.6:

Spark and Scala version mismatch is what causing this. If you use below set of dependencies this problem should be resolved.

One observation I have (which might not be 100% true as well) is if we have spark-core_2.11 (or any spark-xxxx_2.11) but scala-library version is 2.12.X I always ran into issues. Easy thing to memorize might be like if we have spark-xxxx_2.11 then use scala-library 2.11.X but not 2.12.X.

Please fix scala-reflect and scala-compile versions also to 2.11.X

As written by @LuisMiguelMejíaSuárez

As the error clearly says, IO does not have a withFilter method. (You can check the scaladoc here). When you put the type explicitly, you are basically filtering all elements that match such type. And, since the method does not exists, it won't compile. - And no, I do not know any workaround.

But, I can think on at least ne reason of why it should not have it. IO is not exactly a "container" of elements, like List, since it only is a description of a computation, and if you ant to see it like a container it will only had one element, like Option. But, unlike the former, there is not concept of empty IO. Thus, filtering an IO would not make sense.

The workaround that I have found is moving the filter inside another function :

It turns out my pom.xml is configured incorrectly.