Java request credentials from user via ntlm

When you need a Java servlet to trigger NTLM authentication — the kind where the browser automatically sends Windows credentials — setting the WWW-Authenticate: NTLM header and returning a 401 is the server-side trigger. The browser then handles the challenge-response exchange. The doPost receives the auth token for validation.

• Create a servlet like below

import javax.servlet.ServletException;
import java.io.IOException;
import javax.servlet.http.*;

@WebServlet(urlPatterns = {"/servlet/login"})
public class NTLMAuthenticationServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("Asking for creds.....");
        resp.setHeader("WWW-Authenticate", "NTLM");
        resp.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("creds received.....”+req.getHeader("Authorization"));
        
    }
}