ThemeHelper mockThemeHelper = new ThemeHelper() {
            @Override
            protected Path getJarFile(Artifact artifact) {
                return jarPath;
            }
        };

        Artifact artifact = new Artifact("fess-theme-test", "1.0.0");
        Path result = mockThemeHelper.getJarFile(artifact);
        assertEquals(jarPath, result);
    }

    public void test_getJarFile_notExists() {

        final URL classURL = ResourceUtil.getResource(classFilePath);
        final JarURLConnection con = (JarURLConnection) classURL.openConnection();
        ResourceTraversalUtil.forEach(con.getJarFile(), (ResourceHandler) (path, is) -> {
            try {
                if (count < 10) {
                    System.out.println(path);
                }
                System.out.println(path);

     *
     * @param artifact the theme artifact to install
     * @throws ThemeException if installation fails
     */
    public void install(final Artifact artifact) {
        final Path jarPath = getJarFile(artifact);
        final String themeName = getThemeName(artifact);
        if (logger.isDebugEnabled()) {
            logger.debug("Theme: {}", themeName);
        }

     *
     * @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) {

        final URL classURL = ResourceUtil.getResource(classFilePath);
        final JarURLConnection con = (JarURLConnection) classURL.openConnection();
        ClassTraversalUtil.forEach(con.getJarFile(), (ClassHandler) (packageName, shortClassName) -> {
            if (count < 10) {
                System.out.println(ClassUtil.concatName(packageName, shortClassName));
            }

        assertArgumentNotNull("jarUrl", jarUrl);

        final URLConnection con = URLUtil.openConnection(jarUrl);
        if (con instanceof JarURLConnection) {
            return JarURLConnectionUtil.getJarFile((JarURLConnection) con);
        }
        return create(new File(toJarFilePath(jarUrl)));
    }

    /**
     * Returns the path of the JAR file specified by the URL.
     *

                } else if ("jar".equals(resource.getProtocol())) {
                    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();