* Project extensions and conventions (such as `sourceSets`), and extensions on them
* Extensions on the `dependencies` and `repositories` containers, and extensions on them
* Elements in the `tasks` and `configurations` containers
* Elements in <<kotdsl:containers,project-extension containers>> (for example the source sets contributed by the Java Plugin that are added to the `sourceSets` container)

For the main project settings script:

----
plugins {
    id("java-library")
}

sourceSets {
    create("feature")
}

java {
    registerFeature("feature") {
        usingSourceSet(sourceSets["feature"])
    }
}
----
======
[.multi-language-sample]
======
.build.gradle
[source,groovy]
----
plugins {
    id("java-library")
}

sourceSets {
    feature
}

java {

Method <org.gradle.api.tasks.SourceSet.java(groovy.lang.Closure)> has arguments/return type groovy.lang.Closure that is not Gradle public API or primitive or built-in JDK classes or Kotlin classes in (SourceSet.java:0)