Planned lessonJNR-009-L08

Demo: diagnosing an ambiguous-bean startup failure

On This Lesson 3 topics

This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.

In this lesson

read the failure message and fix it three ways; prepares the assessment.

Draft outline details

Add a second PaymentProvider implementation and start the app.
Read the report: it says expected single matching bean but found 2 and lists both names.
Planned mistake: "fix" it by deleting one implementation. Explain why that removes a needed feature.
Fix 1: @Primary on the default. Fix 2: @Qualifier("paypal") at the injection point.
Fix 3: inject Map<String, PaymentProvider> and choose by key at run time.
Run again and confirm the app starts.

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