Planned lessonJNR-012-L05

Demo: typed, validated ShopProperties that fail fast

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

build ShopProperties, see it fail on bad input; prepares JNR-012-LAB1.

Draft outline details

Create the ShopProperties record and enable scanning.
Add shop.currency, shop.tax-rate, shop.page-size-max to application.yml; inject the record into a service.
Add dev and prod profile files with different values.
Planned mistake: set tax-rate: 1.5; the app refuses to start. Read the message ("Binding to target ... failed") and the property name; fix the value.
Override the value with an environment variable and show it winning.

Apply this lesson with the module's lab, exercises and quiz.

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