[Solved] You have two beans of type PaymentService: @Component("creditCardPaymentService") and... How do you inject paypalPaymentService into a client class using constructor injection with @Qualifier? | Spring Boot

Spring Boot - Inversion of Control and Dependency Injection

You have two beans of type PaymentService: @Component("creditCardPaymentService") and @Component("paypalPaymentService"). How do you inject paypalPaymentService into a client class using constructor injection with @Qualifier?

Apublic Client(@Qualifier PaymentService paymentService) { this.paymentService = paymentService; }

Bpublic Client(@Autowired PaymentService paymentService) { this.paymentService = paymentService; }

Cpublic Client(PaymentService paymentService) { this.paymentService = paymentService; }

Dpublic Client(@Qualifier("paypalPaymentService") PaymentService paymentService) { this.paymentService = paymentService; }

Step-by-Step Solution

Solution:

Step 1: Use constructor injection
Constructor injection requires the dependency to be passed as a parameter.
Step 2: Specify bean with @Qualifier
Use @Qualifier("paypalPaymentService") to specify which bean to inject.
Final Answer:
public Client(@Qualifier("paypalPaymentService") PaymentService paymentService) { this.paymentService = paymentService; } -> Option D
Quick Check:
Is @Qualifier used with bean name in constructor? [OK]

Quick Trick: Use @Qualifier with bean name in constructor parameter [OK]

Common Mistakes:

Omitting @Qualifier when multiple beans exist
Using @Qualifier without bean name
Relying on @Autowired alone causing ambiguity

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More Spring Boot Quizzes

How do you inject paypalPaymentService into a client class using constructor injection with @Qualifier?

Step 1: Use constructor injection

Step 2: Specify bean with @Qualifier

Final Answer:

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