Autowire

• In Spring framework, you can wire beans automatically with auto-wiring feature. To enable it, just define the “autowire” attribute in <bean>. 

• You cannot autowire so-called simple properties such as primitives, Strings, and Classes (and arrays of such simple properties). This limitation is by-design.

• no: Default, no auto wiring, set it manually via “ref” attribute

• byName: Auto wiring by property name. If the name of a bean is same as the name of other bean property, auto wire it.

• byType: Auto wiring by property data type. If data type of a bean is compatible with the data type of other bean property, auto wire it.

• constructor: byType mode in constructor argument.

• autodetect: If a default constructor is found, use “autowired by constructor”; Otherwise, use “autowire by type”.