The @Autowired annotation in depth

When @Autowired is used on a dependency, the application context searches for a matching dependency. By default, all dependencies that are autowired are required.

Possible results are as follows:

• One match is found: This is the dependency you are looking for
• More than one match is found: Autowiring fails
• No match is found: Autowiring fails

Cases where more than one candidate is found can be resolved in two ways:

• Use the @Primary annotation to mark one of the candidates as the one to be used
• Use @Qualifier to further qualify autowiring