StandardJavadocDocletOptions header(String header);

    void write(File outputFile) throws IOException;

    @Nullable
    @Internal
    List<String> getSourceNames();

    void setSourceNames(@Nullable List<String> sourceNames);

    MinimalJavadocOptions sourceNames(String... sourceNames);

    void contributeCommandLineOptions(ExecSpec execHandleBuilder);

        if (maxMemory != null && options.getJFlags().stream().noneMatch(flag -> flag.startsWith("-Xmx"))) {
            options.jFlags("-Xmx" + maxMemory);
        }

        options.setSourceNames(sourceNames());

        JavadocSpec spec = createJavadocSpec(options);
        getJavadocToolAdapter().execute(spec);
    }

    private void validateExecutableMatchesToolchain() {

        setEncoding(encoding);
        return this;
    }

    @Override
    public List<String> getSourceNames() {
        return sourceNames.getValue();
    }

    @Override
    public void setSourceNames(List<String> sourceNames) {
        this.sourceNames.setValue(sourceNames);
    }

    @Override
    public MinimalJavadocOptions sourceNames(String... sourceNames) {

        setDestinationDirectory(original.getDestinationDirectory());
        setWindowTitle(original.getWindowTitle());
        setHeader(original.getHeader());
        setSourceNames(copyOrNull(original.getSourceNames()));
    }

    private static <T> List<T> copyOrNull(List<T> items) {
        if (items == null) {
            return null;
        } else {