docs: public static String getAppConfigFolder(String appName) {
        String configRoot = null;
        String osName = System.getProperty("os.name");
        if ("Mac OS X".equals(osName)) {
           configRoot = System.getProperty("user.home") + File.separator + "Library" + File.separator + "Java";
        } else if (osName.startsWith("Windows")) {
           // If on Windows, use the APPDATA environment
           try {
              configRoot = System.getenv("APPDATA");
              if (configRoot != null) {
                 configRoot = configRoot + File.separator + "Sun" + File.separator + "Java"; // FIXME: should be different if using other JVMs from other vendors
              }
           } catch (SecurityException e) {
              // We may be wrapped by a SecurityManager, ignore the exception
           }
        }
        if (configRoot == null) {
           // Use the user.home
           configRoot = System.getProperty("user.home") + File.separator + ".config";
        }
        return configRoot + File.separator + appName;
     }