How to import a proprietary library in Grails 4.0.3 - grails

Question

I am trying to import a proprietary jar lib (ICOMConector.jar) in my grails 4.0.3 project, but it is sending me an error.
In IntelliJ, I right-clicked the project folder and accessed Open Module Settings. Then I clicked in Libraries and chose my jar. Right after, clicked in Module / Dependencies and chose that jar in a compilation scope.
In build.gradle file I put this flatDir, because the jar in my project grails stardard structure:
repositories {
maven { url "https://repo.grails.org/grails/core" }
flatDir {
dirs 'lib'
}
}
And this in the same build.gradle, I've tried all of that, including those now commented,
but the error persists.
dependencies {
//implementation name: 'lib/ICOMConector.jar'
//runtime files('lib/ICOMConector.jar')
//runtime fileTree(dir: 'lib', include: '*.jar')
compile fileTree(dir: 'lib', include: ['*.jar'])
}
when I send grails run-app in the command line, the error is:
| Running application...
startup failed:
/media/alfredo/1TBHDD/CMB/Code projects/Grails 4/detran-mspid/grails-app/init/detran/mspid/BootStrap.groovy: 5: unable to resolve class com.workers.icom.ICOMConector
**# line 5, column 1.
import com.workers.icom.ICOMConector
^
1 error**
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':compileGroovy'.
> Compilation failed; see the compiler error output for details.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
I tried to instantiate the class in Bootstrap.groovy, to make it easier to verify if it is working as expected.
Could anyone help me to import this library. A friend of mine did this in a Spring boot project and it worked, so the problem seems to be a wrong configuration in Grails.
package detran.mspid
import com.workers.icom.ICOMConector
class BootStrap {
def init = { servletContext ->
ICOMConector icom = new ICOMConector()
}
def destroy = {
}
}

Answer 1

This is what I have in my build.gradle for using a library in grails 4.0.3 (been this way since at least grails 3, though). This is almost identical to one you tried with runtime scope.
compile files("lib/opencsv-2.3.jar")
runtimeOnly fileTree(dir: './lib', include: ['*.jar'])
It's entirely possible that either one or both of those is unnecessary...