code: private static boolean isPrintableChar(char c) {
          if (Character.isISOControl(c)) { return false; }
          Character.UnicodeBlock block = Character.UnicodeBlock.of(c);
          return block != null && block != Character.UnicodeBlock.SPECIALS;
      }
docs: From http://stackoverflow.com/questions/220547/printable-char-in-java
  @param c character to test
  @return True if this is a 'normal', printable character, false otherwise