Neither of these is even theoretically possible.  Without knowing some
about the higher-level protocol spoken by the device, there is no
provision in RS232 for a device to provide its name or to signal its
presence.

If you do know something about a higher-level protocol and it allows you
to ask for a device name or detect presence of a device (for example
with some kind of ping), then you need implement those functions
yourself, in whatever way that protocol provides.

You need to look into serial data communication and RS232 in particular.
 There are two lines on the serial port to tell you that a device is
attached, DTR and DSR.

The serial port doesn't have any information about a device
attached to it.  However, if you suspect that the device is
a Hayes-compatable modem, you can interrogate it by
sending an information request command "ATI<num>\r"
where <num> is any number from 0 to 999, but usually
limits out at about 7.  Different modems return various
response strings that you can parse to extract useful information.

Otherwise, anything may be attached to the serial port, and
you would have to know what sort of protocol it talks in order
to recognize it.

Usually, a device raises the DTR-DSR line when it connects, which
you can test using  javax.comm.CommPort.isDSR().

regards,
   Dar7yl