To enable global method security in Spring Security, you should set the prePostEnabled attribute to true in the @EnableGlobalMethodSecurity annotation. This enables the use of @PreAuthorize and @PostAuthorize annotations for method-level security.

The @GetMapping annotation is mainly used to handle HTTP GET requests in a Spring Boot application. It is a specialized annotation that maps HTTP GET requests to specific controller methods. While @RequestMapping is a more generic annotation used for various HTTP methods, @GetMapping specifically targets GET requests, making the code more readable and explicit. The other options are not valid Spring annotations.

To address N+1 select issues in Spring Data JPA while maintaining data consistency, you should implement batch fetching strategies or use join fetch to eagerly fetch related entities. Disabling lazy loading can lead to data inconsistency and is not recommended. Tuning the database server's caching mechanisms can improve performance but doesn't directly address the N+1 issue. Using non-relational databases is a significant architectural change and may not be suitable for all scenarios.

In Spring Boot, the "@ConditionalOnProperty" annotation is used to specify that a bean should be created only under a specific condition based on the values of specified properties. This is a powerful feature that allows developers to control bean creation based on property values, making the application's configuration more flexible and adaptable. The other options are not the correct annotations for this purpose.

In Spring Security, user authentication is primarily handled by the UserDetailsService interface. This interface is responsible for loading user-specific data, such as username, password, and authorities, which is essential for authentication and authorization processes. The Authentication Provider is responsible for authenticating users based on this user-specific data. The Filter Chain and Controller are not primarily responsible for user authentication.

You can customize error messages in Bean Validation in Spring Boot by defining custom error messages using the message attribute within the validation annotations on your entity fields. This approach allows you to specify custom messages for specific validation constraints.

To create a custom validator in Spring Boot, you should extend the Validator interface and implement the validate method. This allows you to define custom validation logic for specific fields in your application. Options 1 and 3 are not correct; Spring Boot does not have an @CustomValidator annotation for field-level validation, and the @Valid annotation is typically used at the method level, not for field-level validation. Option 4 is incorrect as it's not a true statement.

When using JSR-303 Bean Validation, you can validate a field's value against a dynamic value or condition by using @AssertTrue with a custom validation method (Option 2). This method allows you to implement your logic to validate the field against dynamic values or external conditions. Hardcoding the dynamic value directly in the annotation (Option 1) is not flexible and should be avoided.

The @Secured annotation in Spring Security is used to secure methods within a class. It allows you to specify roles or authorities required to access those methods. This is often used for method-level access control.

In Spring Boot, the @ExceptionHandler annotation is used to define a method that should be invoked to handle an exception thrown during the execution of controller methods. This annotation allows you to specify a method that will handle exceptions specific to a particular controller or globally across all controllers. The other options are not used for this purpose in Spring Boot.