Calling a .NET web service from within a Java web app in Tomcat with NTLM / Kerberos

Question

I have a Java webapp that contains an HttpClient to a remote .NET SOAP web service. So far, so good. The Java webapp runs inside Apache Tomcat on a Windows Server and uses a service account.

Unfortunately, that remote .net web service uses NTLM. This answer gives me some insight into how to do it. But it seems that the configuration stills requires a username/password rather than leveraging the service account Tomcat is running with. Also, I'm not sure what the Java authenticator should look like (as seen here).

Has anyone ever attempted this?

Update

Some interesting links:

• Different authentication schemes supported in Apache HTTP Components
• Sample for NTLMv2 authentication - I have yet to test it.

Answer 1

It seems that on Java 7/8 with Tomcat 8.x, the following is enough to leverage NTLM authentication "transparently".

import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.client.methods.HttpUriRequest;

Followed by

boolean useWindowsAuthentication = true;
HttpUriRequest request;
CloseableHttpClient httpclient;
if (useWindowsAuthentication){
    log.info("Using Windows Authentication");
    httpclient = WinHttpClients.createDefault();    
} else {
    httpclient = HttpClients.createDefault();
}