The RedirectStrategy interface presumably exists to enable customization of the way Spring Security implements redirects.
In classes like ConcurrentSessionFilter and SimpleUrlAuthenticationFailureHandler, it is possible to override the default strategy as embodied in DefaultRedirectStrategy, because they contain a public setRedirectStrategy method.
However LoginUrlAuthenticationEntryPoint does not contain such a method. This means that the use of DefaultRedirectStrategy is hardcoded into the class and not possible to override without subclassing.
I do not see a reason why LoginUrlAuthenticationEntryPoint should not allow customization of the RedirectStrategy. It looks like it was simply overlooked.
Therefore I would like to see a public setRedirectStrategy method added to this class. This should be trivial and not affect existing clients.