spring xml context file configured and referred to in main.  via ClassPathXmlApplication() of the Application.  setter injection is used
Constructor Injection wiring Demo instead of setter injection
Autowire=constructor injection - Autowiring byType, byName, constructor
autowire='byType' works using the setter - but a null constructor must be present
autowire='byName'
Component scanner demo - configuring spring xml context: anotationn and component-scan