code: public void removePortOwnershipListener(CommPortOwnershipListener c) {
          LOGGER.fine("CommPortIdentifier:removePortOwnershipListener()");
          /* why is this called twice? */
          if (ownershipListener != null) {
              ownershipListener.removeElement(c);
          }
      }
docs: removes PortOwnership listener
  
  @param c - listener to remove