How to use the "useFirstPass" option of Krb5LoginModule

[lizhong]

Hi all,

    The "useFirstPass" option is mentioned here:
    http://java.sun.com/j2se/1.5.0/docs/guide/security/jaas/spec/com/sun/security/auth/module/Krb5LoginModule.html
    As follows:
    The Krb5LoginModule also recognizes the following additional Configuration options that enable you to share username and passwords across different authentication modules: 

    useFirstPass   if, true, this LoginModule retrieves the
                   username and password from the module's shared state,
                   using "javax.security.auth.login.name" and
                   "javax.security.auth.login.password" as the respective
                   keys. The retrieved values are used for authentication.
                   If authentication fails, no attempt for a retry
                   is made, and the failure is reported back to the
                   calling application.
    
    I tried to set the "javax.security.auth.login.name" property of the system, but why nothing happened? The Krb5loginmodule still didn't find any user name. Could someone tell me the reason?

--
Li Zhong