How to add ressource folder with json with the shadowjar plugin in gradle

Question

Here is my problem, my build gradle with shadowjar works well execept that the src/main/ressources is not added to the jar.

When i try to add include('src/main/ressources') it gives me a main class not found when launching the shadowjar task.

buildscript {
    repositories {
        mavenCentral()
        gradlePluginPortal()
    }
    dependencies {
        classpath "gradle.plugin.com.github.johnrengelman:shadow:7.1.2"
    }
}



apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'application'
apply plugin: 'com.github.johnrengelman.shadow'

// gradle 5.0+ compatibility
configurations.implementation.setCanBeResolved(true)
// gradle 9.0+ compatibility
// for replacing configurations.implementation.setCanBeResolved(true)
// resolve all dependencies at configuration time



// tag::repositories[]
repositories { 
    mavenCentral() 
}



application {
    // Define the main class for the application.
    mainClass = 'd20.App'
}

// end::repositories[]

// tag::dependencies[]
sourceCompatibility = 1.8
targetCompatibility = 1.8

dependencies {
    implementation "joda-time:joda-time:+"
    testImplementation "junit:junit:+"
    implementation 'com.google.code.gson:gson:+'

}



// tag::jar[]
jar {
    archiveBaseName = 'd20'
    archiveVersion =  '0.1.0'
    manifest {
    attributes(
      'Class-Path': configurations.implementation.collect { it.getName() }.join(' '),
      'Main-Class': 'd20.HelloWorld'
    )
  }
}


shadowJar {

   archiveBaseName.set('oldschooljava')



   archiveClassifier.set('')
   archiveVersion.set('')
      
}

// end::jar[]

// tag::dependencies[]
//sourceCompatibility = 1.8
//targetCompatibility = 1.8

//dependencies {
    //implementation "joda-time:joda-time:2.2"
    //testImplementation "junit:junit:4.12"
//}

How can i include the ressources folder in my jar with shadowjar ?

regards