Many of the changes in Spring Security 3 will be visible in the
security namespace style of configuration. Although this chapter cannot cover all of the minor changes in detail, we'll try to cover those changes that will be most likely to affect you as you move to Spring Security 3.
The most obvious changes in Spring Security 3 deal with the configuration of the
AuthenticationManager and any related
AuthenticationProvider elements. In Spring Security 2, the
AuthenticationProvider configuration elements were completely disconnected—declaring an
AuthenticationProvider didn't require any notion of an
AuthenticationManager at all.