IWA and Java

Hi All,

I'm sure this question must have been asked before but after searching
Google and newsgroups I cant seem to find any useful resources.

I am looking for some way to integrate java with Integrated Windows
Authentication (IWA).

I will describe my scenario below and hopefully someone can point me in the
right direction.

Basically I have java program which has lots of screens etc.  I am wanting
to assign individual access rights to each screen (full, edit, view, none)
for each user using an access table I already have designed.  The software
will be running on a windows domain which is set up using active directory.

When my program is loaded I want to be able to get the currently windows
logged on user name and then lookup my access table to see what access they
are allowed/not allowed.

The next step is if they go to do something that they have no access for
then I want to give them the option to change user (within our program, not
change windows logon) which will present them with a logon screen which take
the username given and password given and first authenticates it with active
directory and then check that user is allowed access to that part of the
system.

My problem is that I am not sure how to go about getting the currently
logged on user and how to authenticate username/ passwords with active
directory.

Do I need to right an API in VB to user or is there someway to do this
within java already or as an add-on?

Any help at all would be appreciated.

Regards

Jamie