Jakarta Commons Net

TheServerSide:

This is an Internet protocol suite Java library originally developed by ORO, Inc. This version supports Finger, Whois, TFTP, Telnet, POP3, FTP, NNTP, SMTP, and some miscellaneous protocols like Time and Echo as well as BSD R command support.

It looks like some of the implementations might be a little more low level than some of us might want to deal with, but that’s a ton of protocols to have at your disposal.  Rock on, Jakarta.  Get yer goodies here.