public static boolean isAllLowerCase(String cs) {
		if (cs == null || isEmpty(cs)) {
			return false;
		}
		int sz = cs.length();
		for (int i = 0; i < sz; i++) {
			if (Character.isLowerCase(cs.charAt(i)) == false) {
				return false;
			}
		}
		return true;
	}