1. Spring Boot Core Annotations
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@SpringBootApplication - Entry point of a Spring Boot application (combines
@Configuration,@EnableAutoConfiguration,@ComponentScan). -
@EnableAutoConfiguration - Automatically configures Spring Boot based on dependencies in the classpath.
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@Configuration - Marks a class as a source of bean definitions.
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@ComponentScan - Scans the specified package for Spring beans.
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@Value - Injects a value into a field from properties or environment variables.
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@Bean - Declares a bean in a configuration class.
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@Component - Marks a class as a Spring-managed component.
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@Service - A specialization of
@Component, used for service layer classes. -
@Repository - A specialization of
@Component, used for DAO classes. -
@Controller - Marks a class as a Spring MVC controller.
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@RestController - Combines
@Controllerand@ResponseBodyfor RESTful services. -
@ConfigurationProperties - Binds external configuration properties to a POJO.
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@Import - Imports one or more configuration classes.
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@PropertySource - Specifies the location of an additional property file.
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@ImportResource - Imports XML configuration into the Spring context.
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@EnableScheduling - Enables scheduling support for tasks.
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@EnableAsync - Enables asynchronous method execution using
@Async. -
@SpringBootTest - Used for integration testing with Spring Boot.
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@TestConfiguration - A configuration class used in tests.
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@EnableAspectJAutoProxy - Enables AspectJ-based AOP support.
2. Spring Dependency Injection (DI) Annotations
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@Autowired - Marks a dependency to be injected automatically.
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@Qualifier - Specifies which bean to inject when multiple candidates exist.
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@Inject - Java standard for dependency injection (similar to
@Autowired). -
@Resource - Injects a bean by name.
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@Primary - Marks a bean to be the primary bean when there are multiple candidates.
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@Named - A Java EE alternative to
@Componentfor DI. -
@MockBean - Mocks a Spring bean in testing.
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@InjectMocks - Injects mocked dependencies into the object under test.
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@Mock - Creates a mock of a class for unit testing.
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@Spy - Creates a spy object to track method calls in testing.
3. Spring Security Annotations
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@EnableWebSecurity - Enables Spring Security for the application.
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@Secured - Specifies that a method or class can only be accessed by users with specific roles.
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@PreAuthorize - Defines security expressions for method-level access control.
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@PostAuthorize - Defines security checks after method execution.
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@RolesAllowed - Restricts access to methods based on roles.
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@EnableGlobalMethodSecurity - Enables method-level security annotations such as
@Securedand@PreAuthorize. -
@EnableOAuth2Sso - Enables OAuth2 Single Sign-On support.
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@EnableGlobalAuthentication - Enables global authentication.
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@EnableOAuth2Login - Enables OAuth2 login functionality.
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@PreFilter - Filters parameters before method execution for security.
4. Spring Data JPA Annotations
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@Entity - Marks a class as a JPA entity.
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@Table - Specifies the table name for an entity.
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@Id - Specifies the primary key of the entity.
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@GeneratedValue - Specifies how the primary key is generated.
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@Column - Maps a field to a database column.
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@ManyToOne - Defines a many-to-one relationship.
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@OneToMany - Defines a one-to-many relationship.
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@OneToOne - Defines a one-to-one relationship.
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@ManyToMany - Defines a many-to-many relationship.
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@JoinColumn - Specifies the join column for relationships.
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@JoinTable - Defines a join table for a many-to-many relationship.
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@Transactional - Marks methods or classes as transactional.
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@Query - Defines custom queries in repository methods.
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@TransactionalEventListener - Listens for transactional events.
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@Embeddable - Marks a class as embeddable in entities.
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@EmbeddedId - Specifies a composite primary key.
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@OrderBy - Specifies the order of results in a query.
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@ElementCollection - Defines a collection of simple values or embeddable objects.
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@NotFound - Specifies how to handle a missing relationship in JPA.
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@Fetch - Defines how related entities are fetched (eager/lazy).
5. Spring Web Annotations
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@RequestMapping - Maps HTTP requests to handler methods.
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@GetMapping - Maps HTTP GET requests to handler methods.
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@PostMapping - Maps HTTP POST requests to handler methods.
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@PutMapping - Maps HTTP PUT requests to handler methods.
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@DeleteMapping - Maps HTTP DELETE requests to handler methods.
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@PatchMapping - Maps HTTP PATCH requests to handler methods.
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@RequestParam - Binds request query parameters to method parameters.
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@PathVariable - Binds path variables in the URL to method parameters.
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@RequestBody - Binds HTTP request body to method parameters.
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@ResponseBody - Marks method return values to be written to the HTTP response body.
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@RequestHeader - Binds HTTP request headers to method parameters.
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@CookieValue - Binds cookies to method parameters.
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@RequestMapping(path = "/path/{id}") - Maps path variables in the URL to method parameters.
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@ModelAttribute - Binds request parameters or model attributes to method parameters.
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@ResponseStatus - Marks a method or exception handler with a specific HTTP status code.
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@ExceptionHandler - Handles exceptions thrown in controller methods.
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@RestControllerAdvice - Provides centralized exception handling for REST controllers.
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@SessionAttributes - Binds model attributes to the HTTP session.
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@CrossOrigin - Enables Cross-Origin Resource Sharing (CORS) for controller methods.
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@EnableWebSecurity - Enables Spring Security for your web application.
6. Spring WebFlux Annotations
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@EnableWebFlux - Enables Spring WebFlux for reactive programming.
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@RestController - A combination of
@Controllerand@ResponseBody. -
@RequestMapping - Maps HTTP requests to handler methods.
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@GetMapping / @PostMapping - HTTP method-specific mappings.
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@ResponseBody - Marks method return values to be written to the HTTP response body.
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@RequestBody - Binds HTTP request body to a method parameter.
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@PathVariable - Binds path variables to method parameters.
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@RequestParam - Binds request query parameters to method parameters.
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@RequestHeader - Binds request headers to method parameters.
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@WebFluxTest - Focuses on testing WebFlux controllers in isolation.
7. Spring Actuator Annotations
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@Endpoint - Defines a custom actuator endpoint.
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@ReadOperation - Marks a method as a read operation in a custom endpoint.
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@WriteOperation - Marks a method as a write operation in a custom endpoint.
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@DeleteOperation - Marks a method as a delete operation in a custom endpoint.
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@HealthIndicator - Provides a custom health check for the actuator.
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@Sensitive - Marks data as sensitive and excludes it from actuator endpoints.
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@AuditEvent - Defines custom audit events.
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@MetricTag - Adds tags to metrics in Spring Actuator.
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@EnableActuator - Enables Spring Boot Actuator for monitoring and management.
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@NonNull - Used for marking a field or method argument that cannot be
null.
8. Spring AOP (Aspect-Oriented Programming) Annotations
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@Aspect - Marks a class as an aspect for AOP.
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@Before - Defines advice to be executed before a method execution.
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@After - Defines advice to be executed after a method execution.
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@AfterReturning - Defines advice that runs after a method completes successfully.
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@AfterThrowing - Defines advice that runs if a method throws an exception.
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@Around - Defines advice that wraps around a method execution.
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@DeclareParents - Used to introduce new functionality to a class (aspect).
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@Order - Specifies the order of advice execution.
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@AroundAdvice - Defines an around advice for method execution.
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@DeclareError - Introduces error handling into classes.
9. Spring Testing Annotations
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@SpringBootTest - Loads the full application context for integration testing.
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@WebMvcTest - Focuses on testing Spring MVC controllers.
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@DataJpaTest - Focuses on testing JPA repositories.
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@MockBean - Mocks a Spring bean for testing purposes.
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@TestConfiguration - Declares a configuration class for testing.
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@BeforeEach / @AfterEach - Set up and tear down methods before/after each test.
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@BeforeAll / @AfterAll - Set up and tear down methods before/after all tests.
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@ContextConfiguration - Specifies context configuration for tests.
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@ActiveProfiles - Activates a specific Spring profile for testing.
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@Transactional - Marks a test to run within a transaction, automatically rolling back after test execution.
10. Spring Validation Annotations
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@NotNull - Ensures that a field is not
null. -
@NotEmpty - Ensures that a string, collection, or array is not empty.
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@NotBlank - Ensures that a string is not blank (doesn't allow only whitespace).
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@Size - Ensures the size of a string, collection, or array is within a specified range.
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@Min / @Max - Ensures the value of a number is within the specified range.
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@Email - Ensures the value is a valid email format.
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@Pattern - Ensures that the string matches a given regular expression.
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@Future / @Past - Ensures that a date or time is in the future or past.
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@AssertTrue / @AssertFalse - Ensures that a boolean field is
trueorfalse. -
@DecimalMin / @DecimalMax - Ensures that a decimal value is within the specified range.
