I want to check if a userInput is free from special characters, here is my code: public class ValidateHelper { public boolean userInputContainsNoSpecialCharacters(String input){ Pattern p = Pattern.compile("[a-zA-Z_0-9 ]"); Matcher m = p.matcher(input); boolean b = m.matches(); if (b) return true; else return false; } } This works if I type one character in a textfield -> "a" in the textfield -> the method returns true "ab" in the textfield -> method returns false. can somebody help please? beste regards Daniel