WebJASPIAuthenticator in JBoss AS 7.1.1 and JBoss EAP 6.0.1 calls secureResponse right after validateRequest on a SAM has been called. The only intermediate code is registering the result of the callback handler with the container. The service invocation (e.g. calling a Servlet) is done afterwards, ie after the call to secureResponse.

See the following fragment:

    if (sam != null) {
            result = sam.isValid(messageInfo, clientSubject, messageLayer, appContext, cbh);
        }
 
        // the authentication process has been a success. We need to register the principal, username, password and roles
        // with the container
        if (result) {
            PasswordValidationCallback pvc = cbh.getPasswordValidationCallback();
            CallerPrincipalCallback cpc = cbh.getCallerPrincipalCallback();
 
            // get the client principal from the callback.
            Principal clientPrincipal = cpc.getPrincipal();
            if (clientPrincipal == null) {
                clientPrincipal = new SimplePrincipal(cpc.getName());
            }
 
            // if the client principal is not a jboss generic principal, we need to build one before registering.
            if (!(clientPrincipal instanceof JBossGenericPrincipal))
                clientPrincipal = this.buildJBossPrincipal(clientSubject, clientPrincipal);
 
            this.register(request, response, clientPrincipal, authMethod, pvc.getUsername(),
                    new String(pvc.getPassword()));
 
            if (this.secureResponse)
                sam.secureResponse(messageInfo, new Subject(), messageLayer, appContext, cbh);
        }

However, section 3.8.3.3 of the JSR 196 (JASPIC) spec says that the semantics of secureResponse are as defined in Section 3.8.2.2, which thus means that secureResponse should be called after a service invocation. Figure 1.1 in Section 1.1 shows this as well, and the general flow as described is Section 3.8 also mentions this.

So, in JBoss the sequence is

validateRequest -> secureResponse -> Invoke Service

While the spec seems to say it should be:

validateRequest -> Invoke Service -> secureResponse

In the reference implementation GlassFish the sequence is indeed the latter one.