The most common Spring Boot annotations that are used in microservice applications

As this article’s title suggests, here are the most common Spring Boot annotations that are used in microservice applications:

Note: If you want to see these annotations in code with an example, just continue reading the description here and at the end of the article you will find the link to the next article where each annotation is given in an example code.

1. @SpringBootApplication: This annotation is used to mark the main class of a Spring Boot application. It enables the Spring Boot auto-configuration mechanism and scans the components in the package and its sub-packages.
2. @Service: This annotation is used to mark a class as a service component in a Spring application. It is used to indicate that the class provides a business logic service and should be managed by the Spring container.
3. @Component: This annotation is used to mark a class as a generic Spring component. It is used to define any other type of bean that does not fit into the other specialised annotations.
4. @Configuration: This annotation is used to mark a class as a configuration class. It is used to define Spring beans and configurations using Java-based configuration instead of XML-based configuration.
5. @EnableAutoConfiguration: This annotation is used to enable Spring Boot's auto-configuration mechanism. It automatically configures the application based on the classpath dependencies and other settings.
6. @Autowired: This annotation is used to inject dependencies into a class. It tells Spring to find a bean of the required type and inject it into the annotated field or method parameter.
7. @Value: This annotation is used to inject external values into a class. It is used to read properties from configuration files or environment variables and inject them into the annotated field or method parameter.
8. @RestController: This annotation is used to mark a class as a REST controller in a Spring application. It combines @Controller and @ResponseBody, which means that the class can handle HTTP requests and return a response in JSON, XML or any other format.
9. @RequestMapping: This annotation is used to map a URL pattern to a specific controller method. It can be used to handle different HTTP methods (GET, POST, PUT, DELETE, etc.) and can be used to pass parameters and headers to the method.
10. @GetMapping: This annotation is used to map HTTP GET requests to a specific method in a Spring controller. It is a shortcut for @RequestMapping(method = RequestMethod.GET). You can use it to define a simple method-based endpoint that responds to GET requests.
11. @Repository: This annotation is used to mark a class as a data access layer component. It is used to define database operations and interact with the database.
12. @Entity: This annotation is used to mark a Java class as a persistent entity in JPA (Java Persistence API). It is used to map a Java class to a database table. When you mark a class with @Entity, you can use JPA annotations to define how the class should be mapped to the database.
13. @ExceptionHandler: This annotation is used to handle exceptions in Spring applications. When an exception is thrown during request processing, the method marked with @ExceptionHandler will be called to handle the exception. It allows you to handle exceptions in a centralised location in your application.
14. @Transactional: This annotation is used to mark a method or class as transactional in a Spring application. It is used to ensure that the method or class is executed within a database transaction. If an exception is thrown during the transaction, the transaction will be rolled back.

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link to my other articles:
1. PART ONE: The most common Spring Boot annotations that are used in microservice applications — Now with examples
2. PART TWO: The most common Spring Boot annotations that are used in microservice applications — Now with examples
3. a simple Spring Boot application that uses MySQL and Rest endpoints
2. best practices to follow when developing REST APIs in a microservice application using Spring Boot