In an application's security domain, the first thing that comes to mind is authentication. During the authentication process, an application compares a user's credentials (for example, a username and password or a token) with the information available to it. If these two match, it allows the process to enter the next step. We will follow the next step in the Authorization section.
Spring Security provides features to support a variety of security authentication protocols. In this section, we will focus on basis and form-based authentication.
Spring provides a built-in form for the purpose of form-based authentication. In addition, it lets you define your own customized login form.
Spring gives you the option to use in-memory authentication, in which the username and password will be hardcoded in the application.
An alternative option is to use a customized authentication provider that lets you decide how to authenticate users by program, for example, calling a data layer service...