Difference between and

Question

I\'m learning Spring 3 and I don\'t seem to grasp the functionality behind and .

Answer 1

you can find more information in spring context schema file. following is in spring-context-4.3.xsd

Activates various annotations to be detected in bean classes: Spring's @Required and
@Autowired, as well as JSR 250's @PostConstruct, @PreDestroy and @Resource (if available),
JAX-WS's @WebServiceRef (if available), EJB 3's @EJB (if available), and JPA's
@PersistenceContext and @PersistenceUnit (if available). Alternatively, you may
choose to activate the individual BeanPostProcessors for those annotations.

Note: This tag does not activate processing of Spring's @Transactional or EJB 3's
@TransactionAttribute annotation. Consider the use of the 
tag for that purpose.

Scans the classpath for annotated components that will be auto-registered as
Spring beans. By default, the Spring-provided @Component, @Repository, @Service, @Controller, @RestController, @ControllerAdvice, and @Configuration stereotypes    will be detected.

Note: This tag implies the effects of the 'annotation-config' tag, activating @Required,
@Autowired, @PostConstruct, @PreDestroy, @Resource, @PersistenceContext and @PersistenceUnit
annotations in the component classes, which is usually desired for autodetected components
(without external configuration). Turn off the 'annotation-config' attribute to deactivate
this default behavior, for example in order to use custom BeanPostProcessor definitions
for handling those annotations.

Note: You may use placeholders in package paths, but only resolved against system
properties (analogous to resource paths). A component scan results in new bean definitions
being registered; Spring's PropertySourcesPlaceholderConfigurer will apply to those bean
definitions just like to regular bean definitions, but it won't apply to the component
scan settings themselves.