and:
        file("src/main/java/somepackage/SomeClass.java") << "public class SomeClass { }"
        file("settings.gradle") << "rootProject.name='javaOnly'"

        when:
        run "build"

        then:
        file("build/libs/javaOnly.jar").exists()
    }

    def "supports central repository declaration"() {
        given:
        buildFile << """
plugins {
    id 'groovy'
}

            apply plugin: 'scala'
        """
        settingsFile << """
            rootProject.name = 'javaOnly'
            dependencyResolutionManagement {
                ${mavenCentralRepository()}
            }
        """
        expect:
        succeeds "build"
        file("build/libs/javaOnly.jar").assertExists()
    }

    def "supports central repository declaration"() {
        given:

        // which silently excludes files not ending in .java
        Iterable<File> javaOnly = Iterables.filter(spec.getSourceFiles(), NormalizingJavaCompiler::hasJavaExtension);
        spec.setSourceFiles(ImmutableSet.copyOf(javaOnly));
    }

    private static boolean hasJavaExtension(@Nullable File input) {
        return hasExtension(input, ".java");
    }