private final JavadocOptionFileOption<String> docTitle;
    private final JavadocOptionFileOption<String> footer;
    private final JavadocOptionFileOption<String> bottom;
    private final JavadocOptionFileOption<List<String>> links;
    private final JavadocOptionFileOption<List<JavadocOfflineLink>> linksOffline;
    private final JavadocOptionFileOption<Boolean> linkSource;
    private final JavadocOptionFileOption<Map<String, List<String>>> groups;

    }

    @Issue("https://github.com/gradle/gradle/issues/1456")
    def "can use custom JavadocOptionFileOption type"() {
        buildFile << """
            apply plugin: 'java'
            import org.gradle.external.javadoc.internal.JavadocOptionFileWriterContext;

            class CustomJavadocOptionFileOption implements JavadocOptionFileOption<String> {
                private String value = "foo"

Method <org.gradle.external.javadoc.JavadocOptionFileOption.getOption()> does not have raw return type assignable to org.gradle.api.provider.Provider in (JavadocOptionFileOption.java:0)