Why is Jsch asking for Kerberos username?

Question

I'm using JSch with key based authentication, yet when I try to connect I get asked for a Kerberos username. The code blocks where the comment //blocks here is located.

    final JSch jsch = new JSch();
    jsch.addIdentity(KEYPATH);

    final Session session = jsch.getSession( REMOTE_USERNAME, REMOTE_HOST );
    session.setConfig("StrictHostKeyChecking", "no");
    log.debug("Connecting: ");
    session.connect(); //blocks here
    log.debug("Connected.");