HtmlTagBasedGenerator generator = new HtmlTagBasedGenerator();
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        File outputFile = File.createTempFile("generator_", ".png");

        String imagePath = "thumbnail/600x400.png";
        try (ImageInputStream input = ImageIO.createImageInputStream(classLoader.getResourceAsStream(imagePath))) {
            generator.saveImage(input, outputFile);

        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)) {