code: private char readEscapedChar() throws IOException {
      int ch = getChar();
      switch (ch) {
        case '"' : return '"';
        case '\'' : return '\'';
        case '\\' : return '\\';
        case '/' : return '/';
        case 'n' : return '\n';
        case 'r' : return '\r';
        case 't' : return '\t';
        case 'f' : return '\f';
        case 'b' : return '\b';
        case 'u' :
          return (char)(
                 (hexval(getChar()) << 12)
               | (hexval(getChar()) << 8)
               | (hexval(getChar()) << 4)
               | (hexval(getChar())));
      }
      if ( (flags & ALLOW_BACKSLASH_ESCAPING_ANY_CHARACTER) != 0 && ch != EOF) {
        return (char)ch;
      }
      throw err("Invalid character escape");
    }
docs: backslash has already been read when this is called