import sun.security.jgss.krb5.ServiceCreds; //导入依赖的package包/类
@Override
public Object getServiceCreds(AccessControlContext acc)
        throws LoginException {
    ServiceCreds serviceCreds =
        Krb5Util.getServiceCreds(GSSCaller.CALLER_SSL_SERVER, null, acc);
    return serviceCreds;
}
 

import sun.security.jgss.krb5.ServiceCreds; //导入依赖的package包/类
@Override
public String getServerPrincipalName(Object serviceCreds) {
    return ((ServiceCreds)serviceCreds).getName();
}
 

import sun.security.jgss.krb5.ServiceCreds; //导入依赖的package包/类
@Override
public Object getServiceCreds(AccessControlContext acc) {
    try {
        ServiceCreds serviceCreds = AccessController.doPrivileged(
                (PrivilegedExceptionAction<ServiceCreds>)
                        () -> Krb5Util.getServiceCreds(
                                GSSCaller.CALLER_SSL_SERVER, null, acc));
        if (serviceCreds == null) {
            if (debug != null && Debug.isOn("handshake")) {
                System.out.println("Kerberos serviceCreds not available");
            }
            return null;
        }
        if (debug != null && Debug.isOn("handshake")) {
            System.out.println("Using Kerberos creds");
        }
        String serverPrincipal = serviceCreds.getName();
        if (serverPrincipal != null) {
            // When service is bound, we check ASAP. Otherwise,
            // will check after client request is received
            // in in Kerberos ClientKeyExchange
            SecurityManager sm = System.getSecurityManager();
            try {
                if (sm != null) {
                    // Eliminate dependency on ServicePermission
                    sm.checkPermission(new ServicePermission(
                            serverPrincipal, "accept"), acc);
                }
            } catch (SecurityException se) {
                if (debug != null && Debug.isOn("handshake")) {
                    System.out.println("Permission to access Kerberos"
                            + " secret key denied");
                }
                return null;
            }
        }
        return serviceCreds;
    } catch (PrivilegedActionException e) {
        // Likely exception here is LoginException
        if (debug != null && Debug.isOn("handshake")) {
            System.out.println("Attempt to obtain Kerberos key failed: "
                    + e.toString());
        }
        return null;
    }
}