This subclass of Provider defines methods that allow users to "log in" before using the provider's services. An implementation of the login( ) method should use the supplied javax.security.auth.callback.CallbackHandler class to request the user's password or other authentication credentials. If no callback handler is passed to login( ), it should use the one registered with setCallbackHandler( ) or a default.

Figure 14-3. java.security.AuthProvider

public abstract class AuthProvider extends Provider {
// Protected Constructors
     protected AuthProvider(String name, double version, String info);  
// Public Instance Methods
     public abstract void login(javax.security.auth.Subject subject, javax.
        security.auth.callback.CallbackHandler handler) 
        throws javax.security.auth.login.LoginException;  
     public abstract void logout( ) throws javax.security.auth.login.LoginException;  
     public abstract void setCallbackHandler(javax.security.auth.callback.
        CallbackHandler handler);  
}