public static String maskString(String stringToMask) {
		Assert.notNull(stringToMask, "'stringToMask' must not be null.");
		return stringToMask.replaceAll(".", MASK_CHARACTER);
	}
Masks provided {@link String}s with the {@link PasswordUtils#MASK_CHARACTER}.

@param stringToMask Must not be null
@return The masked String
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/rest/PasswordUtils.java