To support custom permissions in Spring Security, you should implement a custom PermissionEvaluator (Option 2). This interface allows you to define custom logic for evaluating permissions. Creating a custom security interceptor (Option 1) or modifying the Spring Security core library (Option 3) is not recommended and can be complex and error-prone. Predefined permission expressions (Option 4) may not cover all custom requirements.

In Spring Boot, you can access a defined property in the application properties file within a Spring Boot application class by using the @Value annotation. This annotation allows you to inject property values directly into your beans, making it easy to access and use configuration properties within your code. The other options are not standard ways to access properties in Spring Boot.

You can enable transaction management in a Spring Boot application by using the @EnableTransactionManagement annotation. This annotation tells Spring to enable transactional behavior for annotated methods. While you can also annotate methods or classes with @Transactional to specify transactional behavior, you need to enable transaction management globally with @EnableTransactionManagement. Spring Boot does not enable transaction management by default, and configuring transactions in application.properties is not a common approach for enabling transaction management.

When integrating with external APIs in a Spring Boot application, it's crucial to implement a global exception handler (Option 4) to manage failures. This handler should return standardized error responses with clear error messages and appropriate HTTP status codes, ensuring informative messages are relayed back to the user. Implementing a retry mechanism (Option 1) is a good practice, but it should be combined with proper error handling. Options 2 and 3 are not recommended as they either log errors internally or provide generic and uninformative error messages to users.

Option 1 is correct. Enabling garbage collection logging with JVM flags allows you to analyze memory usage patterns and identify memory leaks or excessive memory consumption, which are common causes of OutOfMemoryErrors. Increasing the number of application instances may exacerbate the issue if it's related to memory consumption. Disabling Spring beans or reducing threads may not be suitable solutions for addressing OutOfMemoryErrors.

In projects with multiple beans and dependencies, @Primary should be used to define a default bean when no qualifier is specified. This provides a clear choice when there is ambiguity. However, it should be used judiciously, especially when there are multiple beans of the same type. It should not be overused, as it can lead to unexpected behavior. The other options do not accurately represent best practices for using @Primary.

In Spring Boot, to customize the storage and retrieval of cache, a developer can implement the CacheResolver interface. This interface provides methods to resolve cache instances dynamically. The other options are not standard interfaces for customizing caching in Spring Boot.

The process of supplying an external dependency to an object in Spring is called "Dependency Injection." It involves injecting or providing the required dependencies to an object rather than having the object create them itself, promoting loose coupling and easier testing.

The primary purpose of Auto Configuration in Spring Boot is to reduce application complexity. It achieves this by automatically configuring application components based on dependencies and classpath settings. This simplifies the development process by eliminating much of the manual configuration that would otherwise be required. While security, database access, and network connections are important aspects of an application, they are not the primary focus of Auto Configuration.

In a Spring Boot application, the @Cacheable annotation is used to enable conditional caching of method return values based on the evaluation of a SpEL (Spring Expression Language) expression. By using this annotation, you can specify when a method's result should be cached, which is helpful for optimizing performance in certain scenarios.