Which two mechanisms of autowiring a dependency when multiple beans match the dependency's type are correct? (Choose two.)

Question

Options

• AUse of @Qualifier annotation on the class and @Autowired annotation either on a field or setter
• BUse of @Qualifier and @Autowired annotations together with setter methods.
• CUse of @Qualifier annotation only with setter methods (@Autowired is optional for setters).
• DUse of @Qualifier and @Autowired annotations together on a field.
• EUse of @Qualifier annotation only on a field (@Autowired is optional for fields).

• A
  74% (32)
• B
  5% (2)
• C
  14% (6)
• E
  7% (3)

Explanation

@Qualifier on the class (A) and @Qualifier + @Autowired on a field (D) are the two correct mechanisms. Option A represents qualifying at the bean definition side - placing @Qualifier on the bean's class to label it, then using @Autowired alone on the injection point (field or setter) to let Spring match that qualifier. Option D represents qualifying at the injection point - placing both @Qualifier and @Autowired together on a field, which is the most common pattern for disambiguating multiple matching beans.

Why the distractors are wrong:

• B is incorrect because using @Qualifier + @Autowired on a setter is technically valid Spring behavior, but the question specifically asks for two distinct mechanisms - B describes the same injection-point mechanism as D, just on a setter, making it redundant and therefore not a correct answer choice here.
• C is incorrect because @Autowired is not optional on setter methods - @Qualifier alone won't trigger injection.
• E is incorrect for the same reason - @Qualifier alone on a field does nothing; @Autowired (or @Inject) is required to signal Spring to perform injection.

Memory tip: Think of it as two sides of a bridge - you can stamp the qualifier on the bean class (source side, Option A) or stamp it at the injection point on a field (destination side, Option D). Either way, @Autowired is always required at the injection side to trigger the wiring.

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