Spring - notes

-> light weight framework used to build any type of java apps
-> its non-invasive : does not force a programmer to extend any predefined class (like struts)
-> features :
            -> simplicity (non-invasive)
            -> testability (no need server/container)
            -> lightly coupling

-> modules in spring 1.x :
                          -> core module
                          -> context module (J2EE)
                          -> DAO (JDBC)
                          -> AOP (Aspect oriented Programming)
                          -> ORM module
                          -> web module
                          -> MVC module

-> but web and MVC modules are combined in spring 2.x .

Core Module
-----------------
-> to avoid tightly coupling
-> to achieve loosly coupling

Dependency Injection
------------------------
-> setter/ constructor injection
-> spring ioc container have all beans/dependencies

Get Resource
------------------
-> Resource(I), ClassPathResource(C)

Get Bean
------------------
-> BeanFactory(I), XMLBeanFactory(C)

Object dependency injection
--------------------------------
-> two methods to denote this in config.xml
            -> inner bean
            -> <ref /> tag
-> <ref /> tag can contain any one of the following three attributes
            -> local : both parent and child bean in same configuration file (spring_config1.xml)
            -> parent : two config files (spring_config1.xml for parent and spring_config2.xml for child)
            -> bean : first checking goes on local file, if no, goes to parent file