Spring Security (5.7.3): this.authenticationManager is null - spring-security

Question

I'm trying POST requests to login to the page with JWT Authentication.
I had initially tried to do JWT Authentication using WebSecurityConfigurerAdapter. But WebSecurityConfigurerAdapter is deprecated. I then tried to integrate it according to the new usage.But When I send POST request in Postman, I m getting this error.
"org.springframework.security.authentication.AuthenticationManager.authenticate(org.springframework.security.core.Authentication)" because "this.authenticationManager" is null
My Dependencies are:
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.7.3</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.project</groupId>
<artifactId>questapp</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>questapp</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>17</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-test</artifactId>
</dependency>
<dependency>
<groupId>io.jsonwebtoken</groupId>
<artifactId>jjwt</artifactId>
<version>0.9.1</version>
</dependency>
</dependencies>
My Controller Class is:
#RestController
#RequestMapping("/auth")
public class AuthenticationController {
private AuthenticationManager authenticationManager;
private JwtTokenProvider jwtTokenProvider;
#PostMapping("/login")
public String login(#RequestBody UserRequest userLoginRequest) {
UsernamePasswordAuthenticationToken authenticationToken = new UsernamePasswordAuthenticationToken(userLoginRequest.getUserName(), userLoginRequest.getPassword());
Authentication auth = authenticationManager.authenticate(authenticationToken);
SecurityContextHolder.getContext().setAuthentication(authenticationToken);
String jwtToken = jwtTokenProvider.generateJwtToken(auth);
return "Bearer "+jwtToken;
}
}
My SecurityConfig Class is:
#Configuration
#EnableWebSecurity
#RequiredArgsConstructor
public class SecurityConfig {
private final UserDetailsService jwtUserDetailsService;
private final JwtAuthenticationEntryPoint handler;
#Bean
public JwtAuthenticationFilter jwtAuthenticationFilter() {
return new JwtAuthenticationFilter();
}
#Bean
public AuthenticationManager authenticationManager(HttpSecurity http) throws Exception {
AuthenticationManagerBuilder authenticationManagerBuilder = http.getSharedObject(AuthenticationManagerBuilder.class);
authenticationManagerBuilder.userDetailsService(jwtUserDetailsService).passwordEncoder(new BCryptPasswordEncoder());
return authenticationManagerBuilder.build();
}
#Bean
public CorsFilter corsFilter() {
UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
CorsConfiguration config = new CorsConfiguration();
config.setAllowCredentials(true);
config.addAllowedOrigin("*");
config.addAllowedHeader("*");
config.addAllowedMethod("OPTIONS");
config.addAllowedMethod("HEAD");
config.addAllowedMethod("GET");
config.addAllowedMethod("PUT");
config.addAllowedMethod("POST");
config.addAllowedMethod("DELETE");
config.addAllowedMethod("PATCH");
source.registerCorsConfiguration("/**", config);
return new CorsFilter(source);
}
#Bean
public SecurityFilterChain filterChain(HttpSecurity httpSecurity) throws Exception{
httpSecurity
.cors()
.and()
.csrf().disable()
.addFilterBefore(jwtAuthenticationFilter(), UsernamePasswordAuthenticationFilter.class)
.exceptionHandling().authenticationEntryPoint(handler).and()
.sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS).and()
.authorizeRequests()
.antMatchers(HttpMethod.GET,"/auth/**")
.permitAll()
.antMatchers("/auth/**")
.permitAll()
.anyRequest().authenticated();
return httpSecurity.build();
}
}
Can anyone tell me where I made a mistake?