Qualified injection
In the business framework, you always inject dependencies by interface not by implementation class. For each injection point, two situations are possible: If only one implementation exists for a specific interface, it is injected without ambiguity. If multiple exists for a specific interface, the injection point should be qualified to select the implementation to inject. This done by putting an qualifier annotation along the @Inject annotation. Built-in qualifiers SeedStack provides several built-in qualifiers.