Do you have experience implementing authentication mechanisms using Spring Security?

Yes, I have experience implementing authentication using Spring Security. The process typically includes the following steps:

1. Configuring Spring Security to protect URLs and define access rules.
2. Setting up the authentication mechanism — for example, through a database using UserDetailsService.
3. Implementing a class that loads the user and their roles.
4. Configuring a login form or other mechanisms (JWT, OAuth2).

An example of a basic configuration with a login form:

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests()
                .antMatchers("/public/**").permitAll()
                .anyRequest().authenticated()
                .and()
            .formLogin()
                .loginPage("/login")
                .permitAll();
    }

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication()
            .withUser("user")
            .password(passwordEncoder().encode("password"))
            .roles("USER");
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
}

This example shows simple authentication with an in-memory user and a login form. In real projects, a database and more complex mechanisms are usually used.