# Java Microservices with Spring Cloud Spring Cloud provides tools for developers to quickly build distributed systems and microservices. It offers solutions for common patterns in distributed systems like configuration management, service discovery, circuit breakers, and more. ## Why Microservices? ### Monolithic Challenges - Single point of failure - Difficult to scale individual components - Technology lock-in - Large codebase becomes hard to maintain ### Microservices Benefits - **Independent deployment**: Deploy services separately - **Technology diversity**: Use different technologies per service - **Fault isolation**: Failure in one service doesn't affect others - **Scalability**: Scale services independently based on demand ## Core Spring Cloud Components ### 1. Service Discovery with Eureka Register and discover services dynamically: ```java @SpringBootApplication @EnableEurekaServer public class EurekaServerApplication { public static void main(String[] args) { SpringApplication.run(EurekaServerApplication.class, args); } } ``` ### 2. Service Registration Register your service with Eureka: ```java @SpringBootApplication @EnableEurekaClient public class UserServiceApplication { public static void main(String[] args) { SpringApplication.run(UserServiceApplication.class, args); } } ``` ### 3. Load Balancing with Ribbon Distribute requests across service instances: ```java @RestController public class UserController { @Autowired private LoadBalancerClient loadBalancer; @GetMapping("/users/{id}") public User getUser(@PathVariable Long id) { ServiceInstance instance = loadBalancer.choose("user-service"); // Use instance to make request return userService.findById(id); } } ``` Spring Cloud simplifies microservices development by providing battle-tested solutions for distributed system challenges.