PLAIN SPRING mein, application setup mein KAAFI MANUAL DECISIONS lene padते hain — DataSource KAISE configure karein, Tomcat KAISE embed karein, JSON serialization KAUN SI library use karein, dependency VERSIONS kaise MATCH karein. Ye FLEXIBILITY deta hai, LEKIN TIME lagता hai aur ERROR-PRONE hai.

SPRING BOOT SAB DECISIONS "PRE-MADE" karta hai — @SpringBootApplication annotation, STARTER dependencies, auto-configuration — SAB MILKE, setup ko MINUTES se SECONDS tak LE AATE hain. Behind the scenes, Spring Boot APPS STILL Spring hi use karti hain — ApplicationContext, beans, DI — SAB SAME rehta hai.

// PLAIN SPRING — manual, verbose:
@Configuration
@EnableWebMvc
@ComponentScan("com.example")
public class WebConfig implements WebMvcConfigurer {
    @Bean
    public ViewResolver viewResolver() { /* manual setup */ }
    // + separate Tomcat deployment (WAR file, external server)
}

// SPRING BOOT — concise, automatic:
@SpringBootApplication
public class MyApp {
    public static void main(String[] args) {
        SpringApplication.run(MyApp.class, args);
        // Embedded Tomcat, ViewResolver, JSON — SAB automatic
    }
}