Spring Boot Externalized Configuration and Profiles 2

Question 1

Which Spring Boot annotation enables a configuration class only when a specific profile is active?

Accepted Answer

@Profile

Answer

@Profile on a @Configuration class or @Bean method restricts its registration to when the named profile is active.

Question 2

What is the property key used to activate profiles via application.properties?

Accepted Answer

spring.profiles.active

Answer

spring.profiles.active sets the active profiles; it can hold a comma-separated list of profile names.

Question 3

When a property is defined in both application.properties and an environment variable, which wins by default?

Accepted Answer

Environment variable

Answer

Environment variables have higher precedence than application.properties in Spring Boot's property source order.

Question 4

How should the environment variable SPRING_DATASOURCE_URL be interpreted by Spring Boot?

Accepted Answer

It maps to spring.datasource.url

Answer

Spring Boot's relaxed binding converts uppercase-with-underscores environment variables to dot-separated property names.

Question 5

Which file name pattern loads configuration only when the 'staging' profile is active?

Accepted Answer

application-staging.properties

Answer

Profile-specific files follow the pattern application-{profile}.properties or application-{profile}.yml.

Spring Boot Practice Test