title: Is com port opened in exclusive mode
body: <p>I have created application that sends/receives messages using com port. I use rxtx lib for this purpose. When application starts I open com port like:</p>
  
  <pre><code>    String comportidentifier = "/dev/ttyS0";
  
              CommPortIdentifier portIdentifier = null;
              portIdentifier = CommPortIdentifier.getPortIdentifier(comportidentifier);
  
              if (portIdentifier.isCurrentlyOwned()) {
                  JOptionPane.showMessageDialog(null, "port in use");
              } else {
  
                  SerialPort serialPort = (SerialPort) portIdentifier.open("ReadComPort", 200);
  }
  </code></pre>
  
  <p>And I close it when programm finishes job.</p>
  
  <p>Unexpectedly I found that my comport (the one I have opened) transmits some strange command my code does't sends. I'm usig several libraryes in my code and I don't pass com port variable to them. The only description is that something in system is alsow has opened port and is sends command. But is this possible if I already have opened com port? I suppose that when I have opened port nobody can do that also until I close it. How to describe this situation? </p>
  
  <p>When I have change port to /dev/ttyS1  unexpected command was not transmitted. </p>