What is the purpose of using Ribbon in a microservices architecture in Spring Cloud?
- Data storage
- Handling API requests
- Load balancing
- Service registration
Ribbon is used in a Spring Cloud microservices architecture for load balancing. It distributes incoming requests across multiple instances of a service, improving system reliability and performance.
How do you handle situations where a service registered with Eureka becomes unavailable?
- By configuring Eureka to automatically retry registering the service.
- By implementing a fallback mechanism in the service using tools like Hystrix.
- By re-registering the service manually after it becomes available.
- By using Eureka's built-in circuit breaker mechanism.
When a service registered with Eureka becomes unavailable, you can handle it by implementing a fallback mechanism in the service. Hystrix is a popular choice for this purpose in a Spring Cloud application. It allows you to define a fallback method that will be executed when the primary service is unavailable. This ensures graceful degradation of service and improves system resilience. Configuring Eureka to retry registering the service or using its circuit breaker mechanism is not the primary approach for handling unavailability.
When configuring a CacheManager in Spring Boot, the _____ property can be used to set the TTL values for cache entries.
- cacheExpiry
- evictionTimeout
- expireAfterWrite
- timeToLive
When configuring a CacheManager in Spring Boot, the expireAfterWrite property can be used to set the time-to-live (TTL) values for cache entries. This property determines how long cache entries remain valid before they are considered expired and potentially removed from the cache. It's essential for controlling cache behavior.
The _____ method in Spring Boot reactive programming is used to transform the items emitted by a Publisher.
- filter
- flatMap
- map
- subscribe
In Spring Boot reactive programming, the map method is used to transform the items emitted by a Publisher. The map operation allows you to apply a function to each item emitted by a Publisher and produce a new Publisher with the transformed items. This is a common operation when working with reactive streams to perform data transformations.
In Spring Boot, the properties defined in the _____ file are used to configure the application.
- application.properties
- application.yml
- config.yml
- main.properties
In Spring Boot, the properties defined in the application.yml file are used to configure the application. While you can also use application.properties, YAML configuration files are a popular choice due to their readability and ease of use for defining properties.
To configure the cache storage type, like in-memory or external, in Spring Boot, the _____ property is used.
- spring.cache.cache-type
- spring.cache.storage
- spring.cache.store-type
- spring.cache.type
In Spring Boot, the spring.cache.cache-type property is used to configure the cache storage type. This property allows you to specify whether you want to use an in-memory cache, an external cache, or another type of cache storage for your application's caching needs. Configuring the cache type is essential for optimizing performance and resource usage.
In a Spring Boot application, the HTTP request body can be deserialized using the _____ annotation.
- @PathVariable
- @RequestBody
- @RequestParam
- @ResponseBody
In Spring Boot, the @RequestBody annotation is used to deserialize the HTTP request body into a Java object. This is particularly useful when dealing with POST or PUT requests where data is sent in the request body. The other annotations are used for different purposes, such as specifying response bodies, request parameters, or path variables.
Imagine you are creating a configuration class in Spring Boot that should only be processed if a certain bean is present in the ApplicationContext. How would you accomplish this?
- Create a custom condition class implementing the Condition interface and specify the condition in the configuration class using @Conditional.
- This behavior is not possible in Spring Boot; configuration classes are always processed regardless of the bean's presence.
- Use the @ConditionalOnBean annotation on the configuration class and specify the required bean's class.
- Use the @RequiresBean annotation and specify the required bean's name in the configuration class.
To conditionally process a configuration class based on the presence of a certain bean, you can use the @ConditionalOnBean annotation. This annotation ensures that the configuration class is only processed if the specified bean is present in the ApplicationContext. It's a powerful way to control the activation of configuration based on runtime conditions.
In Spring Boot, which annotation is used to conditionally enable caching only when a certain property is set?
- @Cacheable
- @ConditionalCache
- @ConditionalOnProperty("spring.cache.enabled")
- @EnableCaching
In Spring Boot, you can conditionally enable caching by using the @ConditionalOnProperty annotation with the property name as "spring.cache.enabled." This annotation allows caching to be enabled only when the specified property is set to true. The other annotations do not provide conditional caching based on a property.
To simulate HTTP requests and responses in integration tests, Spring Boot provides the _____ class, allowing for testing of controller methods without starting the server.
- MockMVC
- MockMvc
- TestRestTemplate
- WebMvcConfigurer
Spring Boot provides the MockMvc class, which allows you to simulate HTTP requests and responses for testing controller methods without the need to start a server. It's a crucial tool for integration testing in Spring Boot.