String OS = System.getProperty("os.name").toLowerCase();

public static boolean isWindows() {
	return (OS.indexOf("win") >= 0);
}

public static boolean isMac() {
	return (OS.indexOf("mac") >= 0);
}

public static boolean isUnix() {
	return (OS.indexOf("nix") >= 0 || OS.indexOf("nux") >= 0 || OS.indexOf("aix") > 0 );
}