Java EE's mysterious message policy
Users of Java EE authentication (JASPIC) may have noticed that the initialize method of a SAM takes two parameters of type MessagePolicy . But what are these parameters used for? In this article we'll take a somewhat deeper look. In practice, the overwhelming majority of SAMs only seem to use this MessagePolicy in one way; completely ignore it. As such, there aren't many if any examples available that demonstrate how these passed in policies should actually be enforced. The JASPIC spec isn't quite clear about this either. It does seem to say in a somewhat cryptic way that the isMandatory method is an alias for the "javax.security.auth.message.MessagePolicy.isMandatory" entry in the MessageInfo map, and that the ProtectionPolicy of the TargetPolicy of the MessagePolicy must be ProtectionPolicy.AUTHENTICATE_SENDER and/or ProtectionPolicy.AUTHENTICATE_CONTENT . Pretty much the only example we have in code that at least references the MessagePolicy ty...