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

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

                    final JarURLConnection jarURLConnection = (JarURLConnection) resource.openConnection();
                    try (JarFile jarFile = jarURLConnection.getJarFile()) {
                        final Enumeration<JarEntry> entries = jarFile.entries();
                        while (entries.hasMoreElements()) {
                            final JarEntry entry = entries.nextElement();

        final Set<String> nameSet = new HashSet<>();
        final File[] jarFiles = ResourceUtil.getPluginJarFiles(PluginHelper.ArtifactType.DATA_STORE.getId());
        for (final File jarFile : jarFiles) {
            try (FileSystem fs = FileSystems.newFileSystem(jarFile.toPath(), ClassLoader.getSystemClassLoader())) {
                final Path xmlPath = fs.getPath("fess_ds++.xml");
                try (InputStream is = Files.newInputStream(xmlPath)) {