6 · Advanced · lesson 41 of 41

A Peek at Spring Boot

The most popular Java framework, in one file.

Java

@SpringBootApplication
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

@RestController
class HelloController {
    @GetMapping("/hello")
    String hello(@RequestParam String name) {
        return "Hello, " + name;
    }
}

Run it and http://localhost:8080/hello?name=Ada answers 'Hello, Ada'. Spring uses annotations + reflection to wire the controller, start an embedded Tomcat, and serve HTTP.

Key takeaways

✓Convention over configuration — sensible defaults everywhere.
✓Annotation-driven: @Service, @Repository, @Autowired, @Transactional.

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