How to know Active or open ports on a system

Question

How to know he open ports on a system.
N e idea.
regards,
Rajesh Vincent.

Answer 1

Using the Java Communications API you can use the static method CommPortIdentifier.getPortIdentifiers to enumerate the available ports on the system, like:
Enumeration ports = CommPortIdentifier.getPortIdentifiers();
while (ports.hasMoreElements()) {
  CommPortIdentifier port = (CommPortIdentifier) ports.nextElement();
  switch (port.getPortType()) {
    case CommPortIdentifier.PORT_PARALLEL:
      // it's a parallel port (called port.getName())
      break;
    case CommPortIdentifier.PORT_SERIAL:
      // it's a serial port (called port.getName())
      break;
    default: 
      // WTF?
      break;
}To know whether you can open the port I think you can use the isCurrentlyOwned() method. To open the port use the open(java.lang.String appname, int timeout) method (you'll get a PortInUseException if the port is already in use)