code: public void setVersion(String version)
      {
          if (_state!=__MSG_EDITABLE)
              throw new IllegalStateException("Not EDITABLE");
          if (version.equalsIgnoreCase(__HTTP_1_1))
          {
              _dotVersion=1;
              _version=__HTTP_1_1;
          }
          else if (version.equalsIgnoreCase(__HTTP_1_0))
          {
              _dotVersion=0;
              _version=__HTTP_1_0;
          }
          else if (version.equalsIgnoreCase(__HTTP_0_9))
          {
              _dotVersion=-1;
              _version=__HTTP_0_9;
          }
          else
              throw new IllegalArgumentException("Unknown version");
      }
docs: Set the request version
  @param version the  HTTP version string (eg HTTP/1.1)
  @exception IllegalStateException message is not EDITABLE