Spring Boot — Java Microservices Without the XML Hell

A Java EE application: a WAR file, an application server (WebLogic, WAS, Tomcat), hundreds of lines of XML configuration. Spring Boot says: enough. Embedded server, auto-configuration, executable JAR. A Java application that starts in 3 seconds.

Why Spring Boot¶

The Spring Framework is excellent, but its configuration is verbose. Spring Boot adds opinionated defaults — auto-configuration based on the classpath, embedded Tomcat/Jetty, starter dependencies. spring-boot-starter-web and you have a REST API.

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

@RestController
@RequestMapping("/api/users")
public class UserController {
    @Autowired
    private UserRepository userRepository;

    @GetMapping
    public List<User> getUsers() {
        return userRepository.findAll();
    }
}

No web.xml, no applicationContext.xml. Annotations and conventions. Build: mvn package → executable JAR. Deploy: java -jar app.jar.

Actuator: Production-Ready Features¶

Spring Boot Actuator adds /health, /metrics, and /info endpoints. Monitoring and health checking without a single line of code. Ideal for service discovery (Consul health check → /health endpoint).

Spring Boot for Microservices¶

Each microservice = a standalone Spring Boot JAR. Its own port, its own configuration, its own deployment. Spring Cloud adds service discovery, a config server, and a circuit breaker. A complete ecosystem for Java microservices.

Profiles and Externalized Configuration¶

application.yml + profiles (dev, staging, prod). Environment variables override YAML — 12-factor compliant. Spring Cloud Config Server for centralized configuration.

Spring Boot Is the New Standard for Java¶

If you are writing Java in 2015 and not using Spring Boot, you are doing it wrong. Productivity, conventions, ecosystem. Enterprise Java, finally accessible.