In Spring Boot, you can configure property sources in a specific order by using the spring.config.order property. This property allows you to specify the order in which configuration files are processed, with lower values indicating higher precedence. While other options are used in Spring Boot for property configuration, they do not control the order of property sources.

To use @Secured and @PreAuthorize annotations in Spring Security, you need to enable the prePostEnabled attribute in the security configuration. This attribute enables the use of pre- and post-invocation expression handling.

For custom validation logic in Spring Boot, the isValid method of the ConstraintValidator interface needs to be implemented. This method contains the custom validation logic and is called to validate the annotated field or parameter. The initialize method is used for initializing the validator, and validate is not a method in the ConstraintValidator interface.

In Spring Boot, you can handle exceptions thrown by a controller method using the @ExceptionHandler annotation. This annotation allows you to define methods that can handle specific exceptions or exception types. Using System.out.println() statements is not the recommended way to handle exceptions, and not handling exceptions is not a valid approach. Defining a separate error controller is a possible strategy but less commonly used.

The @Valid annotation in a method signature within a Controller enables request parameter validation for all parameters of the annotated method. This ensures that incoming request parameters are validated against defined constraints before the method is executed. Option 2 is not accurate as the @Valid annotation itself doesn't control whether the method is called or not. Option 3 is incorrect as @Valid is related to input validation, not response validation. Option 4 is also incorrect.

In a Spring Boot application, the @EnableOAuth2AuthorizationServer annotation is used to enable OAuth2 Authorization Server features. This annotation is crucial when you want your Spring Boot application to act as an OAuth2 Authorization Server. It allows you to configure and provide OAuth2 tokens to clients securely.

You can create a custom query method in a Spring Data JPA repository by using the @Query annotation with JPQL (Java Persistence Query Language). This allows you to define custom queries in your repository interface. Extending the CrudRepository interface provides basic CRUD operations but doesn't allow you to create custom queries directly. The @NamedQuery annotation is used for predefined queries in the entity class, and there's no @CustomQuery annotation in Spring Data JPA.

The @ConditionalOnProperty annotation is used in Auto Configuration to define a condition that must be met for a bean to be registered. It allows you to conditionally enable or disable the registration of a bean based on the presence and value of specified properties in the application.properties file.

Spring Data JPA is commonly used in Spring Boot applications to automate the database schema creation and update process. It provides a high-level, object-oriented interface for interacting with databases and generates SQL statements for schema changes automatically. While the other options may interact with databases, they are not specifically designed for automating schema changes in the same way Spring Data JPA does.

Implementing caching in a Spring Boot application brings several benefits, including reduced database load, faster response times, and improved scalability. However, increased application complexity is not a benefit; it's a potential drawback. Caching adds some complexity to the application logic and requires careful management to ensure data consistency and cache invalidation. The other options reflect actual benefits of caching.