Microsoft NT LAN Manager (NTLM) Authentication Protocol implementation in java. This implementation is not OS-specific. It can be used on any platform.
Single-sign-on (SSO) features can't be used with this implementation. To use SSO in windows environment please take a look at http://waffle.codeplex.com/ project.
See NTLM description NtlmDescription.
NTLM can be used in MS Office Communicator / Lync. It also can be used in windows network - Server Message Block (SMB).
See example of usage ntlm-java for NTLM authentication over SIP to connect to MS Office Communicator / Lync: SipExample.
Other similar projects
http://waffle.codeplex.com/ WAFFLE: Windows Authentication Framework (now only windows OS is supported)
http://jcifs.samba.org/ JCIFS is an Open Source client library that implements the CIFS/SMB networking protocol in 100% Java
http://www.ioplex.com/