code: public static boolean isChar(int ch)
     {
        return 0x09 == ch // TAB
           || 0x0a == ch // LF
           || 0x0d == ch // CR
           || (0x20 <= ch && ch <= 0xD7FF) || (0xE000 <= ch && ch <= 0xFFFD) || (0x10000 <= ch && ch <= 0x10FFFF);
  
     }
docs: Returns true if the specified character is a character which may represent markup or character
  data as defined by production [2] in the XML 1.0 specification. <b>Char
  ::=#x9|#xA|#xD|[#x20-#xD7FF]|[#xE000-#xFFFD]|[#x10000-#x10FFFF]</b>
  
  @param ch
  The character to check.