/** Value created out of "java.vm.name", "os.name", and "os.arch" system properties.
     *  Returned by {@link #getPlatform()} and initialized with {@link Detector#getPlatform()}. */
    private static final String PLATFORM = Detector.getPlatform();

    /**
     * Returned an enumeration of known operating systems and initialized with {@link Detector#getOperatingSystem()}.
     */
    private static final Detector.OperatingSystem OPERATING_SYSTEM = Detector.getOperatingSystem();

    public static class Detector {
        public enum OperatingSystem {
            WINDOWS, LINUX, ANDROID, MACOSX, IOS, OTHER;

            /**
             * @return Parsed pre-defined operating system enum
             */
            static OperatingSystem parse(String string) {
                if (string != null){
                    string = string.toLowerCase();

                    if (string.startsWith("windows")) {
                        return OperatingSystem.WINDOWS;
                    } else if (string.startsWith("linux")) {
                        return OperatingSystem.LINUX;
                    } else if (string.startsWith("android")) {
                        return OperatingSystem.ANDROID;
                    } else if (string.startsWith("macosx")) {
                        return OperatingSystem.MACOSX;
                    } else if (string.startsWith("ios")) {
                        return OperatingSystem.IOS;
                    }
                }

                return OperatingSystem.OTHER;
            }
        }

        public static OperatingSystem getOperatingSystem(){
            return OperatingSystem.parse(Detector.getPlatform());
        }
        ...
    }