Swagger UI integration in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add the Swagger UI dependency in Maven's <dependencies> section.

Spring Boot

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>[1]</artifactId>
    <version>3.0.0</version>
</dependency>

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

Aspringfox-swagger-ui

Bspring-boot-starter-web

Cspringfox-swagger2

Dspring-boot-starter-actuator

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'springfox-swagger2' which is for Swagger core but not UI.

Using unrelated Spring Boot starters.

The correct artifactId for Swagger UI integration with Spring Boot using Springfox is springfox-swagger-ui.

2fill in blank

medium

Complete the code to enable Swagger UI in a Spring Boot configuration class.

Spring Boot

@Configuration
@EnableSwagger2
public class SwaggerConfig {

    @Bean
    public Docket api() {
        return new Docket(DocumentationType.SWAGGER_2)
                .select()
                .apis(RequestHandlerSelectors.[1]("com.example"))
                .paths(PathSelectors.any())
                .build();
    }
}

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

AbasePackage

Bany

Cnone

Dregex

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'any' which selects all APIs without filtering.

Using 'regex' which requires a regex pattern, not a package string.

The method basePackage is used to specify the package to scan for API controllers.

3fill in blank

hard

Fix the error in the Swagger UI URL path to access the documentation.

Spring Boot

http://localhost:8080/[1]

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

Aswagger-ui

Bapi-docs

Cv2/api-docs

Dswagger-ui.html

Attempts:

3 left

💡 Hint

Common Mistakes

Using '/swagger-ui' which is not the full path for the UI page.

Using '/v2/api-docs' which is the JSON endpoint, not the UI.

The default Swagger UI page is accessed at /swagger-ui.html in Springfox 3.0.0.

4fill in blank

hard

Fill both blanks to configure Swagger to only document APIs with paths starting with '/api'.

Spring Boot

return new Docket(DocumentationType.SWAGGER_2)
        .select()
        .apis(RequestHandlerSelectors.basePackage("com.example"))
        .paths(PathSelectors.[1]("[2]"))
        .build();

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

Aant

Bregex

C/api/**

D/api/.*

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'regex' with an ant-style pattern.

Using 'ant' with a regex pattern.

Using ant with the pattern /api/** filters paths starting with '/api'.

5fill in blank

hard

Fill all three blanks to customize the Swagger API info with title, description, and version.

Spring Boot

return new Docket(DocumentationType.SWAGGER_2)
        .apiInfo(new ApiInfoBuilder()
            .title("[1]")
            .description("[2]")
            .version("[3]")
            .build())
        .select()
        .apis(RequestHandlerSelectors.any())
        .paths(PathSelectors.any())
        .build();

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

AMy API

BThis API provides user data

C1.0.0

DSwagger UI

Attempts:

3 left

💡 Hint

Common Mistakes

Putting unrelated strings in the wrong fields.

Leaving version empty or using non-semantic versions.

The title, description, and version fields customize the API info shown in Swagger UI.

Practice

1. What is the main purpose of integrating Swagger UI in a Spring Boot project?

easy

A. To improve database performance

B. To generate frontend UI components

C. To handle user authentication automatically

D. To provide a web page that documents and allows testing of your API

Solution

1. Step 1: Understand Swagger UI's role

   Swagger UI creates a friendly web interface to view and test API endpoints.

2. Step 2: Compare options

   Only To provide a web page that documents and allows testing of your API describes this purpose; others relate to unrelated features.

3. Final Answer:

   To provide a web page that documents and allows testing of your API -> Option D

4. Quick Check:

   Swagger UI = API documentation and testing [OK]

Hint: Swagger UI = API docs + testing page [OK]

Common Mistakes:

• Confusing Swagger UI with database tools
• Thinking Swagger handles authentication
• Assuming Swagger generates frontend code

2. Which dependency should you add to a Spring Boot project to enable Swagger UI with springdoc-openapi?

easy

A. springdoc-openapi-starter-webmvc-ui

B. spring-boot-starter-data-jpa

C. spring-boot-starter-web

D. spring-security-oauth2-client

Solution

1. Step 1: Identify the correct starter for Swagger UI

   The springdoc-openapi-starter-webmvc-ui dependency enables Swagger UI integration in Spring Boot.

2. Step 2: Eliminate unrelated dependencies

   Other options relate to web server, database, or security, not Swagger UI.

3. Final Answer:

   springdoc-openapi-starter-webmvc-ui -> Option A

4. Quick Check:

   Swagger UI dependency = springdoc-openapi-starter-webmvc-ui [OK]

Hint: Use springdoc-openapi-starter-webmvc-ui for Swagger UI [OK]

Common Mistakes:

• Adding only spring-boot-starter-web without Swagger
• Using database or security starters by mistake
• Forgetting to add any Swagger-related dependency

3. Given a Spring Boot app with springdoc-openapi-starter-webmvc-ui added, what URL should you visit to see the Swagger UI page?

medium

A. /openapi-ui/index.html

B. /api-docs/swagger-ui.html

C. /swagger-ui/index.html

D. /swagger-ui.html

Solution

1. Step 1: Recall the default Swagger UI path

   springdoc-openapi serves Swagger UI at /swagger-ui/index.html by default.

2. Step 2: Check other options

   Other URLs are incorrect or outdated paths for Swagger UI.

3. Final Answer:

   /swagger-ui/index.html -> Option C

4. Quick Check:

   Swagger UI URL = /swagger-ui/index.html [OK]

Hint: Swagger UI default path ends with /swagger-ui/index.html [OK]

Common Mistakes:

• Using /swagger-ui.html which is deprecated
• Confusing API docs JSON URL with UI URL
• Trying /openapi-ui which is invalid

4. You added springdoc-openapi-starter-webmvc-ui but visiting /swagger-ui/index.html shows 404 error. What is the most likely cause?

medium

A. You did not enable @EnableSwagger2 annotation

B. You need to restart the Spring Boot app after adding dependency

C. You forgot to add spring-boot-starter-web dependency

D. Swagger UI is only available in Spring Boot 3.x and above

Solution

1. Step 1: Check common setup issues

   After adding a new dependency, the app must be restarted to load it properly.

2. Step 2: Evaluate other options

   @EnableSwagger2 is not needed with springdoc-openapi; spring-boot-starter-web is usually present; Swagger UI works on Spring Boot 2.x too.

3. Final Answer:

   You need to restart the Spring Boot app after adding dependency -> Option B

4. Quick Check:

   Restart app after adding Swagger dependency [OK]

Hint: Restart app after adding dependencies to avoid 404 [OK]

Common Mistakes:

• Thinking @EnableSwagger2 is required with springdoc-openapi
• Missing spring-boot-starter-web (usually present)
• Assuming Swagger UI needs Spring Boot 3 only

5. You want to customize the Swagger UI page title and description in your Spring Boot app using springdoc-openapi. Which approach is correct?

hard

A. Add a bean of type OpenAPI and set info title and description

B. Edit the swagger-ui.html file directly in resources

C. Use @EnableSwagger2 annotation with title parameter

D. Set springdoc.swagger-ui.title property in application.properties

Solution

1. Step 1: Understand customization with springdoc-openapi

   Customizing title and description is done by defining an OpenAPI bean with Info details.

2. Step 2: Eliminate incorrect methods

   Editing swagger-ui.html is not recommended; @EnableSwagger2 is for older Swagger versions; springdoc.swagger-ui.title property does not exist.

3. Final Answer:

   Add a bean of type OpenAPI and set info title and description -> Option A

4. Quick Check:

   Customize Swagger UI via OpenAPI bean [OK]

Hint: Customize Swagger UI by defining OpenAPI bean [OK]

Common Mistakes:

• Trying to edit swagger-ui.html manually
• Using outdated @EnableSwagger2 annotation
• Expecting a springdoc property for title customization