Java中如何为Web请求实现Kerberos身份认证？

最近我一直在参照Oracle Java 8官方文档里的Kerberos认证相关内容，折腾着实现Java Web请求的Kerberos身份认证，目前已经写出了部分代码，分享出来给大家参考：

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.Authenticator;
import java.net.PasswordAuthentication;
import java.net.URL;

public class RunHttpSpnego {
    static final String kuser = "username"; // your account name
    static final String kpass = "password"; // your password for the account
    static class MyAuthenticator 

内容的提问来源于stack exchange，提问作者jumpUpToTheCeiling