How can you configure multiple data sources in a Spring Boot application?

  • By creating separate @Configuration classes for each data source.
  • By using multiple instances of the @DataSource annotation.
  • Data sources can't be configured in Spring Boot applications.
  • Using only the application.properties or application.yml file.
To configure multiple data sources in a Spring Boot application, you should create separate @Configuration classes for each data source. These classes should define DataSource beans with distinct properties for each data source. This approach allows you to specify different database configurations for different parts of your application. Using only the properties file or annotations like @DataSource won't provide the required flexibility.

Imagine you are starting a new Spring Boot project where you need to support both web applications and RESTful APIs. How would you set up the project to accommodate both requirements effectively?

  • Create separate controllers and endpoints for web applications and RESTful APIs within the same project. Use appropriate annotations like @Controller and @RestController to distinguish between the two.
  • Create two separate Spring Boot projects, one for web applications and another for RESTful APIs. Deploy and manage them separately to ensure effective support for both requirements.
  • Use a single controller for both web applications and RESTful APIs, and differentiate the requests based on URL patterns and HTTP methods.
  • Utilize Spring Boot's capability to create multiple modules or modules within a monolithic project, separating web application logic from RESTful API logic.
To effectively support both web applications and RESTful APIs in a Spring Boot project, it's best practice to create separate controllers and endpoints, using @Controller for web applications and @RestController for RESTful APIs. This approach ensures clear separation of concerns and allows for different response types and handling for each type of client.

What is the purpose of the @RestController annotation in a Spring Boot application?

  • To define a RESTful web service endpoint.
  • To configure the application's data source.
  • To handle database transactions.
  • To create a user interface.
The @RestController annotation is used in Spring Boot to define a RESTful web service endpoint. It indicates that the class is a controller responsible for handling HTTP requests and returning responses in a RESTful manner. This annotation is essential for building REST APIs in Spring Boot. The other options do not accurately describe the purpose of this annotation.

You are tasked with implementing API Gateway in a Spring Cloud microservices environment. What considerations and configurations would you take into account to ensure proper routing, filtering, and security?

  • Routing based on hardcoded paths.
  • Implementing authentication and authorization filters.
  • Using the same API Gateway for all microservices.
  • No security measures.
Proper API Gateway implementation requires considerations for routing, filtering, and security. Implementing authentication and authorization filters is crucial for security. Hardcoded routing and ignoring security measures are not recommended practices.

What are the security considerations when validating a JWT token in a Spring Boot application?

  • Ensure the JWT token is signed using a strong algorithm and verify the signature.
  • Expose the JWT token in URL parameters for ease of access.
  • Trust all JWT tokens originating from the same issuer.
  • Validate the JWT token only on the client side.
When validating a JWT token in a Spring Boot application, you must ensure that the token is signed using a strong algorithm and verify the signature to ensure its authenticity. Trusting all JWT tokens from the same issuer or exposing tokens in URL parameters are security risks. Validating the JWT token only on the client side is insufficient as it lacks server-side validation.

For optimizing database connection pooling in Spring Boot, adjusting the _____ property is crucial.

  • spring.application.name
  • spring.datasource.maxIdle
  • spring.jpa.hibernate.ddl-auto
  • spring.mvc.view.prefix
For optimizing database connection pooling in Spring Boot, adjusting the spring.datasource.maxIdle property is crucial. This property configures the maximum number of idle database connections in the pool, which can significantly impact the application's performance and resource utilization. By tuning this property, you can ensure efficient database connection management.

How can you optimize the performance of Spring Data JPA repositories when dealing with large datasets?

  • Using the @Query annotation to write custom queries.
  • Increasing the transaction isolation level.
  • Using the @Transactional annotation on repository methods.
  • Using FetchType.LAZY for related entities.
To optimize the performance of Spring Data JPA repositories when dealing with large datasets, it's crucial to write custom queries using the @Query annotation. This allows you to fine-tune the SQL queries and fetch only the necessary data, minimizing the overhead of retrieving large datasets. Other options may be relevant in different contexts, but they do not directly address the issue of optimizing performance with large datasets.

If you want to specify that a configuration will be applied only if a specific class is present, you would use the @_____ annotation in Spring Boot.

  • ConditionalOnClass
  • ConditionalOnMethod
  • ConditionalOnMissingBean
  • ConditionalOnProperty
If you want to specify that a configuration will be applied only if a specific class is present, you would use the @ConditionalOnClass annotation in Spring Boot. This annotation allows you to conditionally apply a configuration based on the presence of a specified class in the classpath. It helps in creating flexible and conditional configurations.

In a Spring Security application, you need to implement a feature where the users' passwords must be rotated every 30 days. How would you approach implementing this feature while maintaining a high level of security?

  • Implementing a scheduled task to periodically check and rotate passwords
  • Implementing a secure password policy and scheduled password rotation task
  • Storing password expiration dates in plaintext in the database
  • Using a weak hashing algorithm for password storage
To implement password rotation while maintaining security, you should follow best practices like using a strong hashing algorithm, enforcing a secure password policy, and implementing a scheduled task to rotate passwords. Storing expiration dates in plaintext or using weak hashing would compromise security.

What is the significance of the @Transactional annotation in Spring Data JPA?

  • It defines the transaction boundaries for the annotated method.
  • It specifies the fetch strategy for the associated entity.
  • It configures the database connection pool.
  • It enables caching for query results.
The @Transactional annotation in Spring Data JPA is used to define transaction boundaries for the annotated method. It ensures that the method is executed within a transaction, and any changes made to the database are either committed or rolled back as a single unit of work. The other options do not accurately describe the purpose of @Transactional in Spring Data JPA.

In Spring Security, which interface is primarily used for authentication and authorization?

  • AuthenticationProvider
  • PasswordEncoder
  • RoleProvider
  • UserDetails
In Spring Security, the primary interface used for authentication and authorization is the AuthenticationProvider. It's responsible for authenticating users based on provided credentials and creating an Authentication object that represents the authenticated user. While UserDetails is important for user details, PasswordEncoder handles password encoding, and RoleProvider is not a standard Spring Security interface.

You need to develop a Spring Boot application where the requirement is to have different request mappings based on the user's role. How would you design the request mappings and controller methods to fulfill this requirement?

  • Use a single controller with complex conditional logic to handle all role-based request mappings.
  • Create separate controllers for each user role, each with its own set of request mappings and controller methods.
  • Embed role information in the request URL and use a single controller to handle all requests, parsing the role from the URL.
  • Use the same request mappings for all user roles and implement role-specific logic within each controller method.
When dealing with role-based request mappings in a Spring Boot application, the best practice is to create separate controllers for each user role, each with its own set of request mappings and controller methods. This approach keeps the codebase clean, organized, and maintainable. Option 2 is the recommended approach, as it follows the principle of separation of concerns. The other options may lead to complex and hard-to-maintain code.