@Configuration in Java

http://docs.spring.io/spring/docs/3.1.x/javadoc-api/org/springframework/context/annotation/Configuration.html

public @interface Configuration

Indicates that a class declares one or more @Bean methods and may be processed by the Spring container to generate bean definitions and service requests for those beans at runtime, for example:

 @Configuration
 public class AppConfig {
     @Bean
     public MyBean myBean() {
         // instantiate, configure and return bean ...
     }
 }

 <beans>
    <context:annotation-config/>
    <bean class="com.acme.AppConfig"/>
 </beans>

vs 

 @Configuration
 @ComponentScan("com.acme.app.services")
 public class AppConfig {
     // various @Bean definitions ...
 }