Learn 20+ Spring and Spring Boot Annotations

Explore the @Component annotation that marks a class as a spring bean and tells the spring container to automatically create and manage that bean in annotation-based configuration.

The autowired annotation automatically injects a spring bean using constructor, setter, or field injection, demonstrated by injecting a veg pizza bean into a pizza controller.

Use the qualifier annotation to tell the spring container which bean to inject when an interface has multiple implementations, such as veg pizza or non-veg pizza.

Use the @Primary annotation to give higher priority to a bean when multiple Spring beans implement the same type, enabling unambiguous injection.

Explore how @Bean creates spring beans in a java-based configuration and how @Configuration marks a configuration class. Learn to define beans, inject dependencies, and use initMethod and destroyMethod for lifecycle.

Learn how stereotype annotations, derived from component, auto-create Spring beans in the three-layer architecture—controller, service, and repository—within a Spring container, using @Controller, @Service, and @Repository.

Learn how Spring eagerly creates beans at application context startup and how @Lazy loads beans on demand, shown with eager and lazy loader examples.

Bind external configurations to a strongly typed string bean using the configuration properties annotation, including nested objects, maps, and a prefix in a Spring Boot application.

Explore how the @Controller and @ResponseBody annotations turn a Java class into a Spring MVC controller, enable request handling with @RequestMapping, and return JSON responses via HTTP.

Discover how the rest controller annotation acts as a shortcut that replaces at controller and at response body annotations to build RESTful services with Spring MVC.

Map web requests to Spring controller methods using the @RequestMapping annotation, configuring base URLs, class- and method-level mappings, multiple URLs, HTTP methods, and producers and consumes attributes.

Learn how the get mapping annotation is a shortcut for request mapping plus http get, map single or multiple urls using the value attribute, and control media types like application/json.

Use @PostMapping and @RequestBody to map http post requests, consume json via application/json, and convert it to a Java object; test with Postman and verify http status 201.

Learn how the @PutMapping annotation maps HTTP put requests to a handler. Use it as a shortcut for @RequestMapping with method put to update a book.

Explain how the delete mapping annotation acts as a shortcut for add request mapping with http delete. Show binding the template variable to the method parameter with a path variable.