code: public static boolean containsNone(String str, char[] invalidChars) {
        if (str == null || invalidChars == null) {
            return true;
        }
        int strSize = str.length();
        int validSize = invalidChars.length;
        for (int i = 0; i < strSize; i++) {
            char ch = str.charAt(i);
            for (int j = 0; j < validSize; j++) {
                if (invalidChars[j] == ch) {
                    return false;
                }
            }
        }
        return true;
    }
docs: <p>Checks that the String does not contain certain characters.</p>
  
  <p>A <code>null</code> String will return <code>true</code>.
  A <code>null</code> invalid character array will return <code>true</code>.
  An empty String ("") always returns true.</p>
  
  <pre>
  GosuStringUtil.containsNone(null, *)       = true
  GosuStringUtil.containsNone(*, null)       = true
  GosuStringUtil.containsNone("", *)         = true
  GosuStringUtil.containsNone("ab", '')      = true
  GosuStringUtil.containsNone("abab", 'xyz') = true
  GosuStringUtil.containsNone("ab1", 'xyz')  = true
  GosuStringUtil.containsNone("abz", 'xyz')  = false
  </pre>
  
  @param str  the String to check, may be null
  @param invalidChars  an array of invalid chars, may be null
  @return true if it contains none of the invalid chars, or is null
  @since 2.0