>Hi Victor thanks for you time, the examples you posted only deal with a known host which is not what I need, I need to scan a LAN for hosts and then query the port

doh! There is some sample code to do that here:
https://www.quora.com/How-do-I-get-IP-Address-of-all-computers-in-a-network-using-java

....Maybe you can combine the two somehow. Of course this is only for IPv4 networks.