Default Auto Wiring in Spring

Spring can auto wire the beans by following method.

1. byName

Default auto wiring happens in spring byType 

How it works:
Auto wiring by property datatype. Spring container looks at the properties of the beans on which autowire attribute is set. It then tries to match and wire a property if its type matches with exactly one of the beans name in configuration file. If match found instance is injected to the property.
 If more than one such beans exists, exception is thrown by the container.