Many thanks to John, Abbas and Darkangel for their informative replies.
Initially I will simply establish a socket to port 5432 of the server.
This is trivial to do in Java, quick to succeed (or fail), and
provides appropriate information. Something (notionally) like this
(for future googlers !!!)...
<snip>
try {
InetAddress address = InetAddress.getByName("192.168.1.2");
Socket dbSocket = new Socket(address, 5432);
dbSocket.close();
return true;
} catch (Exception e) {
return false;
}
</snip>
Many thanks,
-Damian