Chapter 5: Complete Annotation Dictionary (A-Z)

Quick reference of all Spring Boot annotations, sorted alphabetically. For detailed code examples, see chapters 1 to 4.

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A

Annotation	Description
@ActiveProfiles	Activates specific Spring profiles for unit tests. Allows loading application-test.yml for example.
@After	(JUnit 4) Executes code after each test method.
@AfterClass	(JUnit 4) Executes code after all test methods in a class.
@AfterEach	(JUnit 5) Executes code after each test method. Replaces @After.
@Async	Executes a method asynchronously in a separate thread. Requires @EnableAsync.
@AutoConfigureDataJpa	Automatically configures JPA for a unit test.
@AutoConfigureJsonTesters	Automatically configures JSON serialization/deserialization tools for tests.
@AutoConfigureMockMvc	Automatically configures the MockMvc object for a unit test.
@AutoConfigureWebTestClient	Automatically configures the WebTestClient for WebFlux tests.
@Autowired	Automatically injects a dependency (Spring bean) into a class. Prefer constructor injection.

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B

Annotation	Description
@Bean	Declares a method that returns an object managed by the Spring container. Used in @Configuration classes.
@Before	(JUnit 4) Executes code before each test method.
@BeforeClass	(JUnit 4) Executes code before all test methods in a class.
@BeforeEach	(JUnit 5) Executes code before each test method. Replaces @Before.

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C

Annotation	Description
@Cacheable	Caches the result of a method. Subsequent calls return the cached result.
@CacheConfig	Configures cache settings (name, lifespan, max size) for an entire class.
@CacheEvict	Removes one or all cache entries when the method is called.
@CachePut	Updates the cache with the method result, never using the existing cache.
@CircuitBreaker	(Spring Cloud) Protects a method from repeated failures by limiting calls when the service is down.
@Column	Configures the mapping of a JPA property to a database column (name, nullable, unique, length).
@Component	Marks a class as a generic Spring bean, automatically detected by component scan.
@ComponentScan	Scans packages to automatically detect classes annotated with @Component, @Service, @Repository, etc.
@Conditional	Conditions the creation of a bean based on a custom condition.
@ConditionalOnClass	Creates a bean only if a specific class is present in the classpath.
@ConditionalOnMissingBean	Creates a bean only if no other bean of the same type already exists.
@ConditionalOnProperty	Creates a bean only if a property has a certain value in the configuration.
@Configuration	Marks a Spring configuration class containing @Bean methods.
@ConfigurationProperties	Binds a group of configuration file properties to a Java object (e.g., app.mail.host).
@Controller	Marks a class as a Spring MVC controller that returns views (HTML templates).
@ControllerAdvice	Defines a global advisor for all controllers (centralized exception handling, binding, etc.).
@CrossOrigin	Allows cross-origin HTTP requests (CORS) from specific domains or all domains.

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D

Annotation	Description
@DataJpaTest	Specialized test that loads only the JPA layer (repositories, EntityManager, in-memory DB).
@DeleteMapping	Shortcut for @RequestMapping(method = DELETE). Maps a method to an HTTP DELETE request.
@Disabled	(JUnit 5) Temporarily disables a unit test without removing it from the code.

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E

Annotation	Description
@EnableAsync	Enables asynchronous execution in the application. Necessary for @Async to work.
@EnableCaching	Enables caching in the application. Necessary for @Cacheable to work.
@EnableConfigurationProperties	Enables automatic binding of configuration properties to @ConfigurationProperties objects.
@EnableJms	Enables JMS (Java Message Service) support for messaging in the application.
@EnableJpaRepositories	Enables support for Spring Data JPA repositories. Automatically configured by Spring Boot.
@EnableScheduling	Enables task scheduling. Necessary for @Scheduled to work.
@EnableWebMvc	Enables Spring MVC configuration. Rarely necessary as Spring Boot enables it automatically.
@EnableWebSecurity	Enables custom Spring Security configuration.
@EnableMethodSecurity	Enables method-level security (@PreAuthorize, @PostAuthorize, @Secured).
@Entity	Marks a class as a JPA entity, mapped to a database table.
@Enumerated	Defines how a Java enum is stored in the DB: STRING (text) or ORDINAL (number).
@EventListener	Listens for Spring events (application startup, custom events, etc.).
@ExceptionHandler	Handles a specific exception in a controller or @ControllerAdvice. Returns a custom error response.
@ExtendWith	(JUnit 5) Extends test functionalities with extensions (e.g., SpringExtension, MockitoExtension).

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F

Annotation	Description
@Fallback	(Spring Cloud) Provides a fallback method when a @CircuitBreaker method fails.
@FlywayTest	Tests Flyway database migrations in integration tests.
@Formula	(Hibernate) Defines a SQL-side calculated column, without a physical column in the database.

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G

Annotation	Description
@GeneratedValue	Defines the automatic generation strategy for the primary key (IDENTITY, SEQUENCE, UUID, AUTO).
@GetMapping	Shortcut for @RequestMapping(method = GET). Maps a method to an HTTP GET request.

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I

Annotation	Description
@Id	Marks a field as the primary key of a JPA entity.
@Import	Imports other configuration classes into a @Configuration class.
@InitBinder	Customizes data binding between HTTP requests and Java objects (conversion, validation, formatting).

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J

Annotation	Description
@JoinColumn	Defines the foreign key column for a JPA relationship (@ManyToOne, @OneToOne).
@JoinTable	Defines the join table for a @ManyToMany relationship (table name, join columns).
@JmsListener	Defines a method that listens for JMS messages on a queue or topic.
@JsonFormat	Customizes JSON serialization format (dates, numbers). E.g., @JsonFormat(pattern = "yyyy-MM-dd").
@JsonIgnore	Excludes a property from JSON serialization/deserialization.
@JsonInclude	Controls which properties are included in JSON (e.g., exclude null values).
@JsonProperty	Renames a property in JSON. E.g., @JsonProperty("full_name") for a fullName field.
@JsonSubTypes	Defines subtypes for polymorphic JSON deserialization.
@JsonTest	Specialized test for JSON serialization/deserialization only.
@JsonTypeInfo	Adds type information in JSON to allow polymorphic deserialization.
@JsonView	Filters JSON properties according to the requested view (e.g., public view vs admin view).

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L

Annotation	Description
@Lazy	Delays bean initialization until its first use. Improves startup time.
@Lob	Indicates a Large Object field: CLOB (long text) or BLOB (binary).

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M

Annotation	Description
@ManyToMany	Defines a many-to-many relationship between two JPA entities. Uses a join table.
@ManyToOne	Defines a many-to-one relationship. The "Many" side holds the foreign key.
@MessageMapping	(WebSocket/STOMP) Maps a method to a messaging destination.
@MessagingGateway	(Spring Integration) Defines a gateway interface for sending messages.
@MockBean	Replaces a Spring bean with a Mockito mock in a test.
@MockMvc	Injects a MockMvc instance to simulate HTTP requests in tests.
@ModelAttribute	Binds HTTP request parameters to a Java object. Also used to add attributes to the MVC model.
@Modifying	Indicates that a @Query method executes an UPDATE or DELETE (not a SELECT).

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N

Annotation	Description
@NamedQuery	Defines a named JPQL query directly on an entity.
@NamedQueries	Groups multiple @NamedQuery on the same entity.

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O

Annotation	Description
@OneToMany	Defines a one-to-many relationship between two JPA entities. The "One" side is the parent.
@OneToOne	Defines a one-to-one relationship between two JPA entities.
@Order	Defines the priority order of a bean. The smaller the number, the higher the priority.

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P

Annotation	Description
@PatchMapping	Shortcut for @RequestMapping(method = PATCH). Partial update of a resource.
@PathVariable	Extracts a variable from the URL path. E.g., /users/\{id\} → @PathVariable Long id.
@PostAuthorize	Checks authorizations after method execution (can check the returned value).
@PostConstruct	Executes a method just after all bean dependencies are injected.
@PostMapping	Shortcut for @RequestMapping(method = POST). Creation of a new resource.
@PreAuthorize	Checks authorizations before method execution. Supports SpEL expressions.
@PreDestroy	Executes a method just before the bean is destroyed (cleanup, closing connections).
@Primary	Defines the default bean when multiple beans of the same type exist.
@Profile	Activates a bean or configuration only for certain profiles (dev, test, prod).
@PutMapping	Shortcut for @RequestMapping(method = PUT). Full replacement of a resource.

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Q

Annotation	Description
@Qualifier	Specifies which bean to inject when multiple beans of the same type exist.
@Query	Defines a custom JPQL or native SQL query on a repository method.

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R

Annotation	Description
@Repository	Marks a class as a data access layer. Enables SQL exception translation to Spring exceptions.
@RequestBody	Deserializes the HTTP request body (JSON) into a Java object.
@RequestHeader	Extracts the value of an HTTP header (Authorization, Content-Type, User-Agent, etc.).
@RequestMapping	Base annotation to map a URL to a controller or method. Can specify the HTTP method.
@RequestParam	Extracts a parameter from the query string. E.g., /search?name=Java → @RequestParam String name.
@RequestPart	Extracts a part of a multipart HTTP request (files, uploaded images).
@ResponseBody	Forces a method to return JSON/XML directly in the HTTP response body.
@ResponseStatus	Defines the HTTP status code returned by a method (200, 201, 204, 404, etc.) or an exception.
@RestClientTest	Specialized test for REST clients. Loads only the client configuration.
@RestController	Combination of @Controller + @ResponseBody. Each method returns JSON directly.
@RestControllerAdvice	Combination of @ControllerAdvice + @ResponseBody. Global exception handling for REST APIs.
@Retryable	(Spring Retry) Automatically retries a method in case of failure (e.g., network or DB error).
@RolesAllowed	(JSR-250) Specifies allowed roles for a method. Standard alternative to @Secured.

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S

Annotation	Description
@Scheduled	Schedules periodic execution of a method (fixedRate, fixedDelay, cron). Requires @EnableScheduling.
@Scope	Defines the scope of a bean: singleton (default), prototype, request, session, application.
@Secured	Specifies required roles to access a method. Simpler than @PreAuthorize.
@SendTo	(WebSocket/STOMP) Specifies the response destination for a WebSocket message.
@Service	Marks a class as a business logic layer. Detected by component scan.
@SessionAttributes	Stores model attributes in the HTTP session between requests.
@SessionScope	Defines the scope of a bean as HTTP session (one bean per user session).
@SpyBean	Wraps a real bean with a Mockito spy in tests (real calls except those stubbed).
@SpringBootApplication	Application entry point. Combines @Configuration, @EnableAutoConfiguration, and @ComponentScan.
@SpringBootTest	Loads the full Spring context for integration tests.
@Sql	Executes SQL scripts before or after a test to prepare or clean the database.

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T

Annotation	Description
@Table	Customizes the table name, schema, uniqueness constraints, and indexes for a JPA entity.
@Test	(JUnit) Marks a method as a unit test.
@TestConfiguration	Provides Spring configuration specific to tests (test beans, mocks).
@Timeout	(JUnit 5) Sets a maximum execution time for a test. The test fails if the time is exceeded.
@Transactional	Manages DB transactions. Commits on success, rolls back on exception. readOnly = true optimizes reads.
@TransactionalEventListener	Listens for a Spring event and executes it only after the transaction commit (or rollback).
@Transient	Excludes a field from JPA persistence (no database column).

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V

Annotation	Description
@Valid	Enables Bean Validation on an object (@NotNull, @Size, @Email, etc.).
@Validated	Spring variant of @Valid with support for validation groups.
@Value	Injects a value from the configuration file. E.g., @Value("${app.name}"). Supports default values and SpEL.
@ValueSource	(JUnit 5) Provides input values to a parameterized test.

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W

Annotation	Description
@WebFluxTest	Specialized test for WebFlux controllers (reactive programming).
@WebMvcTest	Specialized test that loads only the MVC controller layer (no DB, no real services).
@WebTestClient	Injects a WebTestClient to simulate HTTP requests in WebFlux tests.

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Validation Annotations (Bean Validation)

Annotation	Description
@NotNull	The field cannot be null.
@NotEmpty	The field cannot be null or empty (String, Collection, Map).
@NotBlank	The field cannot be null, empty, or contain only spaces.
@Size(min, max)	The size must be between min and max (String, Collection).
@Min(value)	The numeric value must be greater than or equal to value.
@Max(value)	The numeric value must be less than or equal to value.
@Email	The field must be a valid email address format.
@Pattern(regexp)	The field must match the given regular expression.
@Positive	The number must be strictly positive (> 0).
@PositiveOrZero	The number must be positive or zero (>= 0).
@Negative	The number must be strictly negative (< 0).
@Past	The date must be in the past.
@Future	The date must be in the future.
@DecimalMin	The decimal value must be greater than or equal to the minimum.
@DecimalMax	The decimal value must be less than or equal to the maximum.

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Statistics

In summary

This dictionary covers 120+ annotations distributed in:

• Core Spring: ~25 annotations (IoC, DI, configuration, lifecycle)
• Web / REST: ~20 annotations (mapping, parameters, responses, errors)
• Data / JPA: ~20 annotations (entities, relationships, queries, transactions)
• JSON / Jackson: ~7 annotations (format, filter, ignore)
• Security: ~7 annotations (config, authorization)
• Cache: ~5 annotations (cacheable, evict, put, config)
• Async / Scheduling: ~5 annotations
• Test: ~25 annotations (JUnit, Spring Test, mocks)
• Validation: ~15 annotations (Bean Validation)
• Messaging: ~5 annotations (JMS, WebSocket)
• Cloud / Resilience: ~3 annotations (CircuitBreaker, Retry, Fallback)

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