What does the @Primary annotation do, and how does it differ from @Qualifier?

@Primary marks one bean as the default choice among multiple candidates of the same type — when Spring needs to autowire and finds several matches, it picks the @Primary one automatically without any extra hint at the injection point. @Qualifier, by contrast, is specified at the injection point itself and lets you pick a DIFFERENT (non-primary) bean explicitly when needed — @Primary sets a sensible default, @Qualifier overrides it case-by-case.