What is the difference between BeanPostProcessor and init/destroy method in Spring?

Question

What is the difference between implementing the BeanPostProcessor interface and either using the init/destroy method attributes in the XML

Answer 1

Just a short supplement to all the answers above: If you have any generic logic, common logic that needs to be universally applied to all your Spring beans, such as the injection of a logger to your beans, setting of a properties file, setting default values to fields of your beans through reflection; you could put that logic into ONE single place: the @Overriden callbacks (eg: postProcessBeforeInitialization(Object arg0, String arg1) if you are implementing the BeanPostProcessor interface); instead of duplicating the same logic across all your beans.