In Spring Boot, the _____ annotation is used to conditionally enable a configuration based on the presence of a specific property.

  • @ComponentScan
  • @ConditionalOnProperty
  • @ConfigurationProperties
  • @EnableAutoConfiguration
In Spring Boot, the "@ConditionalOnProperty" annotation is used to conditionally enable a configuration based on the presence of a specific property. This annotation allows you to configure components or beans based on the values of properties, making it a powerful tool for conditional configuration in your application.

Which of the following is true about the deleteById method of a JpaRepository?

  • It deletes an entity by its primary key.
  • It marks the entity as deleted but does not remove it from the database.
  • It deletes all entities in the repository.
  • It deletes an entity based on a custom query.
The deleteById method of a JpaRepository deletes an entity from the database by its primary key. It is a convenient method for removing specific entities based on their unique identifier. The other options do not accurately describe the behavior of this method; in particular, it does not mark the entity as deleted without removing it from the database.

Which annotation is used in Spring Security to secure methods based on role-based conditions?

  • @Permission
  • @PostAuthorize
  • @PreAuthorize
  • @Secured
The @Secured annotation in Spring Security is used to secure methods based on role-based conditions. You can specify the required roles in the annotation, and only users with those roles can access the method.

In a Spring Boot application, how would you secure microservices using OAuth2 and JWT?

  • It's not possible to secure microservices using OAuth2 and JWT in Spring Boot.
  • Secure each microservice individually by implementing OAuth2 and JWT security for each service, and use a centralized authentication server for token validation.
  • Secure microservices individually with OAuth2 and use API keys for JWT-based authentication.
  • Use a single OAuth2 authentication server to issue JWT tokens and secure all microservices with the same token.
In a Spring Boot application, to secure microservices using OAuth2 and JWT, the best practice is to secure each microservice individually. Each microservice should implement OAuth2 and JWT security, and a centralized authentication server can be used for token validation. This approach ensures that each microservice has its own security context and can enforce its own authorization rules. Securing all microservices with a single token is not recommended, as it can lead to security vulnerabilities if one microservice is compromised.

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

  • To allow configuration classes.
  • To define a main method.
  • To enable Spring MVC support.
  • To enable component scanning.
The @SpringBootApplication annotation in Spring Boot is a convenience annotation that adds all of the following: @Configuration, @EnableAutoConfiguration, and @ComponentScan. Thus, it enables component scanning, allowing Spring to automatically discover and register beans. This is crucial for allowing the Spring context to be aware of all the components, services, repositories, etc. available in the project.

For implementing client credentials grant in a Spring Boot application, the client must send a request to the token endpoint with _____ grant type.

  • authorization_code
  • implicit
  • client_credentials
  • password
To implement the client credentials grant in a Spring Boot application, the client must send a request to the token endpoint with the client_credentials grant type. This grant type is used when the client, typically a service or application, needs to authenticate itself directly with the authorization server to obtain an access token. The other options are different OAuth2 grant types used for various scenarios.

How do you ensure fault tolerance and resilience in microservices developed with Spring Cloud?

  • Avoiding microservices altogether
  • Implementing Circuit Breaker patterns with tools like Hystrix
  • Increasing microservices complexity
  • Using synchronous communication between microservices
To ensure fault tolerance and resilience in Spring Cloud microservices, you should implement Circuit Breaker patterns using tools like Hystrix. This helps prevent cascading failures and allows graceful degradation when a service is experiencing issues.

What is the primary role of a Resource Server in OAuth2?

  • Authenticating users and granting permissions.
  • Generating access tokens for clients.
  • Protecting and serving protected resources.
  • Storing user credentials and data.
The primary role of a Resource Server in OAuth2 is to protect and serve protected resources. It validates access tokens presented by clients and enforces access control to ensure that only authorized clients can access protected resources. It does not generate access tokens (which is the responsibility of the Authorization Server), authenticate users, or store user credentials or data.

Imagine you need to integrate a Spring Security application with an external OAuth2 provider for authentication. How would you design the interaction between the components to ensure secure authentication?

  • Use OAuth2 as a replacement for Spring Security since it handles authentication.
  • Use Spring Security's OAuth2 support to integrate with the external provider securely.
  • Implement a custom authentication mechanism without using OAuth2.
  • Store user credentials and perform authentication locally without involving external providers.
To integrate a Spring Security application with an external OAuth2 provider securely, you should use Spring Security's OAuth2 support. It provides the necessary components to interact securely with external OAuth2 providers, ensuring secure authentication. The other options suggest using OAuth2 incorrectly, implementing a custom mechanism, or storing user credentials locally, which is not recommended for OAuth2 integration.

In Spring Security, how would you handle the situation where a user needs multiple roles for accessing different resources?

  • Assign a composite role that includes all the required roles to the user.
  • Define a separate authentication filter for each resource and specify the required roles in the filter configuration.
  • Use a custom AccessDecisionVoter to evaluate the user's roles and grant access accordingly.
  • Create multiple user accounts, each with a different role, for accessing different resources.
In Spring Security, when a user needs multiple roles for accessing different resources, you can assign a composite role to the user. This composite role should include all the required roles for accessing those resources. Option 2 is not a recommended approach as it would lead to code duplication. Option 3 is a more complex solution and might not be necessary for this scenario. Option 4 is not an efficient way to handle role-based access control.