assertArgumentNotNull("jarFile", jarFile);

        try {
            jarFile.close();
        } catch (final IOException e) {
            logger.log(format("ECL0017", e.getMessage()), e);
        }
    }

     *
     * @param jarFile
     *            the Jar file (must not be {@literal null})
     * @param handler
     *            the handler to process resources (must not be {@literal null})
     */
    public static void forEach(final JarFile jarFile, final ResourceHandler handler) {
        assertArgumentNotNull("jarFile", jarFile);
        assertArgumentNotNull("handler", handler);

                if (form.jarFile == null) {
                    throwValidationError(messages -> messages.addErrorsPluginFileIsNotFound(GLOBAL, form.id), this::asListHtml);
                }
                if (!form.jarFile.getFileName().endsWith(".jar")) {
                    throwValidationError(messages -> messages.addErrorsFileIsNotSupported(GLOBAL, form.jarFile.getFileName()),

                                            <label for="jarFile" class="col-md-3 text-sm-right col-form-label"><la:message
                                                    key="labels.plugin_jar_file"/></label>
                                            <div class="col-md-9 text-sm-right col-form-label">
                                                <input id="jarFile" type="file" name="jarFile" class="form-control-file"/>

         * @param rootDir
         *            The root directory.
         */
        public JarFileTraverser(final JarFile jarFile, final String rootPackage, final String rootDir) {
            this.jarFile = jarFile;
            this.rootPackage = rootPackage;
            this.rootDir = rootDir;
        }

        /**
         * Constructs an instance.
         *
         * @param url

     * </p>
     *
     * @param jarFile the Jar file (must not be {@literal null})
     * @param handler the handler to process classes (must not be {@literal null})
     */
    public static void forEach(final JarFile jarFile, final ClassHandler handler) {
        assertArgumentNotNull("jarFile", jarFile);
        assertArgumentNotNull("handler", handler);

        if (jarFile.getName().toLowerCase().endsWith(WAR_FILE_EXTENSION)) {

        for (final WebResource possibleJar : possibleJars) {
            if (possibleJar.isFile() && possibleJar.getName().endsWith(".jar")) {
                try (final JarFile jarFile = new JarFile(possibleJar.getCanonicalPath())) {
                    final Manifest manifest = jarFile.getManifest();
                    if (manifest != null && manifest.getEntries() != null) {
                        final Attributes attributes = manifest.getMainAttributes();

     *
     * @param conn
     *            {@link JarURLConnection}. Must not be {@literal null}.
     * @return {@link JarFile}
     */
    public static JarFile getJarFile(final JarURLConnection conn) {
        assertArgumentNotNull("conn", conn);

        try {
            return conn.getJarFile();
        } catch (final IOException e) {

    /**
     * Default constructor.
     */
    public InstallForm() {
        // Default constructor
    }

    /** JAR file containing the plugin to install */
    public MultipartFormFile jarFile;

        if (jarFiles == null) {
            return nameSet.stream().sorted().collect(Collectors.toList());
        }
        for (final File jarFile : jarFiles) {
            try (FileSystem fs = FileSystems.newFileSystem(jarFile.toPath(), ClassLoader.getSystemClassLoader())) {
                final Path xmlPath = fs.getPath("fess_ds++.xml");
                if (!Files.exists(xmlPath)) {