spring @Autowire property vs setter

Question

What is the difference between anotate @Autowired to a property or do it in the setter?

As far as I know they both have the same result, but is there any reason to use o

Answer 1

Autowiring works best when it is used consistently across a project. If autowiring is not used in general, it might be confusing to developers to use it to wire only one or two bean definitions. With @Autowired on a field you don't need a setter method, which, on one hand makes the class smaller and easier to read, but on the other hand makes mocking the class a bit uglier.

Explicit dependencies in property and constructor-arg settings always override autowiring. You cannot autowire so-called simple properties such as primitives, Strings, and Classes (and arrays of such simple properties). This limitation is by-design.

Autowiring is less exact than explicit wiring. Spring is careful to avoid guessing in case of ambiguity that might have unexpected results, the relationships between your Spring-managed objects are no longer documented explicitly.

Wiring information may not be available to tools that may generate documentation from a Spring container.

Multiple bean definitions within the container may match the type specified by the setter method or constructor argument to be autowired. For arrays, collections, or Maps, this is not necessarily a problem. However for dependencies that expect a single value, this ambiguity is not arbitrarily resolved. If no unique bean definition is available, an exception is thrown.