Explanation: The various methods of the HttpServletRequest interface are as follows: getRemoteUser(): It returns the user name that is used for the client authentication. The value of the getRemoteUser() method returns null if no user is authenticated. isUserInRole(): It determines whether the remote user is granted a specified user role. The value of the isUserInRole() method returns true if the remote user is granted the specified user role; otherwise it returns false. getUserPrincipal(): It determines the principle name of the current user and returns the java.security.Principal object. The java.security.Principal object contains the remote user name. The value of the getUserPrincipal() method returns null if no user is authenticated. Answer: A is incorrect. It is not defined in the HttpServletRequest interface. The getCallerIdentity() method is used to obtain the java.security.Identity of the caller.