ejb-security-interceptors quickstart has several issues

try {
    if (desiredUser != null && connectionUser != null
            && (desiredUser.getName().equals(connectionUser.getName()) == false)) {
        // The final part of this check is to verify that the change does actually indicate a change in user.
        try {
            // We have been requested to switch user and have successfully identified the user from the connection
            // so now we attempt the switch.
            cachedSecurityContext = SecurityActions.securityContextSetPrincipalInfo(desiredUser,
                    new OuterUserCredential(connectionUser));
            // keep track that we switched the security context
            contextSet = true;
            SecurityActions.remotingContextClear();
        } catch (Exception e) {
            logger.error("Failed to switch security context for user", e);
            // Don't propagate the exception stacktrace back to the client for security reasons
            throw new EJBAccessException("Unable to attempt switching of user.");
        }
    }

    return invocationContext.proceed();
} finally {
    // switch back to original security context
    if (contextSet) {
        SecurityActions.securityContextSet(cachedSecurityContext);
    }
}