case "classes":
                            // first one is "main" from Java sources
                            artifact name: 'main', version: '', extension: '', type: 'java-classes-directory'
                            // second one is "main" from Groovy sources
                            artifact name: 'main', version: '', extension: '', type: 'java-classes-directory'
                            break

Secondary variants (*)
    - Variant : classes
       - Attributes
          - org.gradle.category            = library
          - org.gradle.dependency.bundling = external
          - org.gradle.jvm.version         = 11
          - org.gradle.libraryelements     = classes
          - org.gradle.usage               = java-api
       - Artifacts
          - build/classes/java/main (artifactType = java-classes-directory)

     * A set of Jar files or directories containing compiled code.
     */
    public Set<File> getClasses() {
        return classes;
    }

    /**
     * A set of Jar files or directories containing source code.
     */
    public void setClasses(Set<File> classes) {
        this.classes = classes;
    }

    /**
     * A set of Jar files or directories containing javadoc.
     */
    public Set<File> getJavadoc() {

        index.assertHasOverallResult("failures")

        index.assertHasFailedTest('classes/org.gradle.failing.SomeIgnoredSomePassedSomeFailed', 'failed')

        index.assertHasIgnoredTest('classes/org.gradle.ignoring.SomeIgnoredSomePassed', 'ignored')
        index.assertHasIgnoredTest('classes/org.gradle.failing.SomeIgnoredSomePassedSomeFailed', 'ignored')

        def apiElements = [attributes(Usage.JAVA_API, LibraryElements.JAR, 8),
                           attributes(Usage.JAVA_API, LibraryElements.CLASSES, 8)]
        def runtimeElements = [attributes(Usage.JAVA_RUNTIME, LibraryElements.JAR, 8),
                               attributes(Usage.JAVA_RUNTIME, LibraryElements.CLASSES, 8)]

        when:
        def candidates = [

    <property name="build.dir" value="target"/>
    <property name="classes.dir" value="${build.dir}/classes"/>

    <target name="compile">
        <mkdir dir="${classes.dir}"/>
        <javac srcdir="${src.dir}" destdir="${classes.dir}" debug="true"/>
    </target>

    <target name="package" depends="build">
        <jar destfile="${build.dir}/lib/hello-app.jar" basedir="${classes.dir}"/>
    </target>

    /**
     * Retain only those classes in the keep package hierarchies, plus any classes that are reachable from these classes.
     */
    abstract val keepPackages: SetProperty<String>

    /**
     * Do not rename classes in the unshaded package hierarchies. Always includes 'java'.
     */
    abstract val unshadedPackages: SetProperty<String>

    /**

                // Java types
                new DefaultType(
                        Type.JAR, Language.JAVA_FAMILY, "jar", null, false, JavaPathType.CLASSES, JavaPathType.MODULES),
                new DefaultType(Type.JAVADOC, Language.JAVA_FAMILY, "jar", "javadoc", false, JavaPathType.CLASSES),

"""

        expect:
        succeeds 'classes'

        when: 'update interface, compile should fail'
        file("src/main/${language.name}/IPerson.${language.name}").text = extendedInterface

        then:
        def failure = fails 'classes'
        failure.assertHasDescription "Execution failed for task ':${language.compileTaskName}'."
    }

    def "recompiles dependent classes across project boundaries"() {
        given:

    <orderEntry type="sourceFolder" forTests="false"/>
    <orderEntry type="module-library" scope="RUNTIME">
      <library>
        <CLASSES>
          <root url="jar://@CACHE_DIR@/commons-collections/commons-collections/3.2.2/@SHA1@/commons-collections-3.2.2.jar!/"/>
        </CLASSES>
        <JAVADOC/>
        <SOURCES>