Innerbeans,aliases and injecting object

* constructor injection (how to implement in xml, name and index
*Injecting objects (how to inject object in a bean, ref parameter  for bean)
* InnerBeans, Aliases and idref 
  = innerBean (if the ref bean is only accessible in the bean, how to define in application context.xml) 
  = Aliases (giving different name to the same bean)
  = use id instead of name for tags in bean since id should be unique
  = idref  should be used inorder to tell the xml validation that id should be used as a tag for bean