Spring Security auto-configuration in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable Spring Security auto-configuration in a Spring Boot application.

Spring Boot

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.[1](Application.class, args);
    }
}

Drag options to blanks, or click blank then click option'

Astart

Brun

Claunch

Dexecute

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' or 'launch' instead of 'run' causes compilation errors.

Forgetting to call any method to start the application.

The SpringApplication.run() method starts the Spring Boot application and triggers auto-configuration including Spring Security.

2fill in blank

medium

Complete the code to add a dependency that triggers Spring Security auto-configuration in Maven's pom.xml.

Spring Boot

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-[1]</artifactId>
</dependency>

Drag options to blanks, or click blank then click option'

Asecurity

Bweb

Cdata-jpa

Dthymeleaf

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'web' or 'data-jpa' does not enable security auto-configuration.

Forgetting to add the security starter dependency.

Adding 'spring-boot-starter-security' dependency activates Spring Security auto-configuration.

3fill in blank

hard

Fix the error in the code to disable Spring Security auto-configuration in a Spring Boot test.

Spring Boot

@SpringBootTest(
  exclude = [1].class
)
public class SecurityDisabledTest {}

Drag options to blanks, or click blank then click option'

AEnableWebSecurity

BWebSecurityConfigurerAdapter

CSecurityAutoConfiguration

DSecurityFilterChain

Attempts:

3 left

💡 Hint

Common Mistakes

Excluding WebSecurityConfigurerAdapter does not disable auto-configuration.

Using EnableWebSecurity or SecurityFilterChain classes here is incorrect.

To disable Spring Security auto-configuration, exclude SecurityAutoConfiguration.class.

4fill in blank

hard

Fill both blanks to customize HTTP security by disabling CSRF and permitting all requests.

Spring Boot

@Configuration
@EnableWebSecurity
public class SecurityConfig {
    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        http.csrf().[1]();
        http.authorizeHttpRequests().anyRequest().[2]();
        return http.build();
    }
}

Drag options to blanks, or click blank then click option'

Adisable

BpermitAll

Cauthenticated

Denable

Attempts:

3 left

💡 Hint

Common Mistakes

Using csrf().enable() instead of disable() causes errors.

Using authenticated() instead of permitAll() restricts access.

Calling csrf().disable() turns off CSRF protection. permitAll() allows all requests without authentication.

5fill in blank

hard

Fill both blanks to create a password encoder bean using BCryptPasswordEncoder.

Spring Boot

@Configuration
public class PasswordConfig {
    @Bean
    public [1] passwordEncoder() {
        return new [2]();
    }
}

Drag options to blanks, or click blank then click option'

APasswordEncoder

BBCryptPasswordEncoder

CPasswordEncoderImpl

DSecurityConfig

Attempts:

3 left

💡 Hint

Common Mistakes

Using PasswordEncoderImpl which does not exist.

Returning SecurityConfig instead of a password encoder.

The method returns a PasswordEncoder interface implemented by BCryptPasswordEncoder class instance.

Practice

1. What happens when you add spring-boot-starter-security to a Spring Boot project without any additional configuration?

easy

A. The application runs without any security restrictions.

B. All web endpoints are secured with a default login page.

C. Only REST endpoints are secured, web pages remain open.

D. The application throws an error due to missing configuration.

Solution

1. Step 1: Understand default behavior of spring-boot-starter-security

   Adding this starter enables Spring Security auto-configuration which secures all web endpoints by default.

2. Step 2: Recognize the default login page

   Spring Security provides a default login page automatically when no custom security config is provided.

3. Final Answer:

   All web endpoints are secured with a default login page. -> Option B

4. Quick Check:

   Default security = secured endpoints + login page [OK]

Hint: Default security locks all endpoints with login page [OK]

Common Mistakes:

• Thinking endpoints remain open without config
• Assuming only REST endpoints are secured
• Believing an error occurs without config

2. Which of the following is the correct way to disable Spring Security auto-configuration in a Spring Boot application?

easy

A. @Configuration(exclude = SecurityAutoConfiguration.class)

B. @EnableAutoConfiguration(exclude = SecurityAutoConfiguration.class)

C. @ComponentScan(exclude = SecurityAutoConfiguration.class)

D. @SpringBootApplication(exclude = SecurityAutoConfiguration.class)

Solution

1. Step 1: Identify the correct annotation to exclude auto-configuration

   Spring Boot allows excluding auto-configurations via the exclude attribute in @SpringBootApplication.

2. Step 2: Confirm the correct class to exclude

   The class to exclude for disabling security auto-configuration is SecurityAutoConfiguration.class.

3. Final Answer:

   @SpringBootApplication(exclude = SecurityAutoConfiguration.class) -> Option D

4. Quick Check:

   Disable auto-config = exclude in @SpringBootApplication [OK]

Hint: Exclude SecurityAutoConfiguration in @SpringBootApplication [OK]

Common Mistakes:

• Using @EnableAutoConfiguration instead of @SpringBootApplication
• Trying to exclude in @ComponentScan or @Configuration
• Not specifying the correct class to exclude

3. Given this Spring Boot application with spring-boot-starter-security added and no custom security config, what will happen when a user accesses /hello endpoint?

 @RestController
 public class HelloController {
   @GetMapping("/hello")
   public String hello() {
     return "Hello World";
   }
 }

medium

A. The user sees "Hello World" without login.

B. The endpoint returns 404 Not Found.

C. The user is redirected to a login page before seeing "Hello World".

D. The application throws a runtime exception.

Solution

1. Step 1: Recall default security behavior with no custom config

   All endpoints are secured and require authentication by default.

2. Step 2: Understand access flow to /hello endpoint

   Accessing /hello triggers Spring Security to redirect to the default login page before allowing access.

3. Final Answer:

   The user is redirected to a login page before seeing "Hello World". -> Option C

4. Quick Check:

   Default security = login redirect before access [OK]

Hint: No config means login page before any endpoint access [OK]

Common Mistakes:

• Assuming endpoints are open without login
• Expecting 404 error for existing endpoint
• Thinking runtime exception occurs

4. You added spring-boot-starter-security but your application fails to start with a bean creation error related to AuthenticationManager. What is the likely cause?

medium

A. You defined a custom SecurityFilterChain but forgot to expose an AuthenticationManager bean.

B. You did not add spring-boot-starter-web dependency.

C. You excluded SecurityAutoConfiguration but still use security annotations.

D. You have multiple @SpringBootApplication classes.

Solution

1. Step 1: Understand the error context with AuthenticationManager bean

   When customizing security by defining a SecurityFilterChain, Spring Boot no longer auto-configures AuthenticationManager.

2. Step 2: Identify missing bean definition

   You must manually expose an AuthenticationManager bean to satisfy dependencies.

3. Final Answer:

   You defined a custom SecurityFilterChain but forgot to expose an AuthenticationManager bean. -> Option A

4. Quick Check:

   Custom filter chain needs AuthenticationManager bean [OK]

Hint: Custom SecurityFilterChain requires AuthenticationManager bean [OK]

Common Mistakes:

• Blaming missing web dependency
• Ignoring need for AuthenticationManager bean
• Assuming multiple @SpringBootApplication causes this error

5. You want to customize Spring Security auto-configuration to allow public access to /public/** endpoints but secure all others with form login. Which configuration snippet correctly achieves this?

hard

A. Define a SecurityFilterChain bean with http.authorizeHttpRequests().requestMatchers("/public/**").permitAll().anyRequest().authenticated().and().formLogin().

B. Exclude SecurityAutoConfiguration and manually configure WebSecurityConfigurerAdapter to permit /public/**.

C. Add @EnableWebSecurity and override configure(HttpSecurity http) to permit /public/** and disable form login.

D. Add @SpringBootApplication(exclude = SecurityAutoConfiguration.class) and use http.csrf().disable().

Solution

1. Step 1: Use SecurityFilterChain bean to customize security rules

   Spring Security 5.7+ recommends defining a SecurityFilterChain bean for custom rules.

2. Step 2: Permit /public/** and require authentication for others with form login

   The method chain authorizeHttpRequests().requestMatchers("/public/**").permitAll().anyRequest().authenticated().and().formLogin() correctly sets these rules.

3. Final Answer:

   Define a SecurityFilterChain bean with http.authorizeHttpRequests().requestMatchers("/public/**").permitAll().anyRequest().authenticated().and().formLogin() -> Option A

4. Quick Check:

   Permit public paths + secure others + form login = Define a SecurityFilterChain bean with http.authorizeHttpRequests().requestMatchers("/public/**").permitAll().anyRequest().authenticated().and().formLogin(). [OK]

Hint: Use SecurityFilterChain bean with permitAll and formLogin [OK]

Common Mistakes:

• Excluding auto-config and using deprecated WebSecurityConfigurerAdapter
• Disabling form login when it is required
• Misusing @EnableWebSecurity without proper bean