The Refresh Token's purpose in OAuth2 is to enable the client to obtain a new access token without requiring the user to reauthenticate. It helps maintain the session's continuity by ensuring that the client can access protected resources even after the initial access token expires. The other options are not the primary purposes of the Refresh Token.

When cache entries are not being evicted as expected, it's crucial to check and correct the cache eviction policy configuration. Increasing timeout values may not solve the problem and could lead to stale data. Monitoring cache utilization and memory consumption helps identify issues. Restarting the application is a heavy-handed approach and may not address the root cause.

In a Spring Cloud microservices architecture, Eureka is primarily used for allowing services to discover each other. Eureka is a service registry and discovery server that enables microservices to find and communicate with each other. When a service starts up, it registers itself with Eureka, making it discoverable by other services. Eureka maintains a dynamic directory of available services, allowing for automatic load balancing and failover.

Configuring global method security allows you to set default security settings for all methods, which simplifies security setup. Standard configurations require you to annotate each method individually for security settings.

The ordering of Auto Configurations can be controlled using the @AutoConfigureOrder annotation or the spring.autoconfigure.order property. This allows you to specify the order in which Auto Configurations should be applied during the application startup process. The lower the value, the earlier the configuration is applied.

When dealing with complex dynamic queries in Spring Data JPA, it's recommended to use the Criteria API. It provides type-safety, flexibility, and better maintainability compared to native SQL queries. Combining multiple queries into a monolithic one may hinder maintainability and lead to performance issues due to unnecessary data retrieval. Using the findAll method and filtering in your application code can be inefficient, causing the N+1 select issue.

To provide global exception handling across all @Controller classes in Spring Boot, you can use the @ControllerAdvice annotation. It allows you to define global exception handling logic that can be applied to multiple controllers.

The @Repository annotation in Spring Boot is used specifically for data access operations. It is a specialization of @Component and is used to indicate that the class defines a data repository. @Component, on the other hand, is a more general-purpose annotation for defining Spring beans. @Repository is used to simplify data access configuration and exception translation.

In Spring Boot, the @Validated annotation is used along with specific constraint annotations like @NotBlank, @Min, @Max, etc., to apply validation constraints on a field. The @Validated annotation indicates that the validation should be performed on the annotated field or method parameter. It is a fundamental part of Spring Boot's validation framework.

To conditionally apply caching logic in Spring Boot, developers use the @Cacheable annotation. This annotation allows them to specify conditions under which the caching logic should be applied, typically by providing a SpEL (Spring Expression Language) expression. It's a powerful tool for selectively caching method results.