code: public static void printJsonCodePoint(Appendable out, int codePoint)
          throws IOException
      {
          // JSON only allows double-quote strings.
          printCodePoint(out, codePoint, EscapeMode.JSON);
      }
docs: Prints a single Unicode code point for use in an ASCII-safe JSON string.
  
  @param out the stream to receive the data.
  @param codePoint a Unicode code point.