code: public static synchronized PortRange getTcpSourceInstance() {
          if (tcpSourcePortRange == null) {
              tcpSourcePortRange = new PortRange();
              tcpSourcePortRange.init(
                    CoGProperties.getDefault().getTcpSourcePortRange());
          }
          return tcpSourcePortRange;
      }
docs: Returns PortRange instance for TCP source sockets.
  If the tcp.source.port.range property is set, the class
  will be initialized with the specified port ranges.
  
  @return PortRange the default instace of this class.