Net iD – Java
An integration based on Jave is not a separate integration path, you can chose to work with either the SunPKCS11 Provider or the The SunMSCAPI Provider. Maybe you will find SunPCSC useful as well.
More reading can be found here
Bug in JRE
If you want to download av applet from a webpage protected by mutual SSL/TLS you will have some trouble. Jave does not inherit the session from the browser (as in JRE 1.3 or older). Instead it want to establish it’s own session with it’s own certificate selection dialog. And in this case it handles key in a strange way (bug!).
Should work for you: (serverside SSL/TLS)
Will probably not work for you: (mutual SSL/TLS)