Tip
	For those unfamiliar with AOP and/or Spring AOP, you'll want to take a look Chapter 6 of the core Spring reference documentation, Aspect-oriented Programming with Spring.

A configuration class can serve 'double duty' as an aspect. By applying @Aspect to a @Configuration class, you can then add pointcuts and advice that will be applied against all beans in the container.

@Aspect
@Configuration
public class AppConfig {
    @Bean
    public Service service() {
        return new ServiceImpl(...);
    }

    @Before("execution(* service..Service+.set*(*))")
    public void trackServicePropertyChange() {
        logger.info("property changed on service!");
    }
}

This pointcut will match the all methods starting with 'set' on all implementations of the Service interface. Before any matching methods execute, the trackServicePropertyChange() method will be executed.

To create a reusable aspect, define a class annotated with @Configuration and Aspect containing advice methods and pointcuts.

@Aspect
@Configuration
public class PropertyChangeTracker {
    private Logger logger = Logger.getLogger(PropertyChangeTracker.class);

    @Before("execution(* set*(*))")
    public void trackChange() {
        logger.info("property just changed...");
    }
}

Then include that aspect in the application context, either using the @Import annotation or by adding at as a constructor argument when instantiating JavaConfigApplicationContext. Examples of both approaches are below.

@Configuration
@Import(PropertyChangeTracker.class)
@Aspect // necessary in order to have transferService bean get aspects applied!
public class MyConfig {
    @Bean
    public TransferService myService() {
        return new TransferServiceImpl(...);
    }
}

...

JavaConfigApplicationContext context = new JavaConfigApplicationContext(MyConfig.class);

or...

@Aspect // necessary in order to have transferService bean get aspects applied!
@Configuration
public class MyConfig {
    @Bean
    public TransferService myService() {
        return new TransferServiceImpl(...);
    }
}

...

JavaConfigApplicationContext context =
    new JavaConfigApplicationContext(MyConfig.class, PropertyChangeTracker.class);

	Note
	Annotating Configuration classes with @Aspect to enable AOP functionality is not consistent with the standard semantics around the @Aspect annotation, and would thus likely be un-intuitive to someone familiar with XML configuration. This approach to applying aspects will change prior to JavaConfig's 1.0 GA release. See SJC-55 for details.