Best way to check for all alphabetic, alphanumeric or numeric strings

The best way of checking whether the string is a pure alphabetic, alphanumeric or numeric is to use the String class's matches method by using the regex pattern as a parameter.

  if ("!abc123".matches("[a-zA-Z]*")) {
      System.out.println("Pure alphabetic string");
  } else {
      System.out.println("Not pure alphabets");
  }