@Profile for environment-specific beans in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the @Profile annotation in Spring Boot?

The @Profile annotation is used to mark beans that should only be created when a specific environment or profile is active. It helps manage environment-specific configurations easily.

beginner

How do you activate a Spring profile when running your application?

You can activate a Spring profile by setting the spring.profiles.active property, for example in application.properties or as a command-line argument: --spring.profiles.active=dev.

intermediate

Can a bean have multiple profiles using @Profile? How?

Yes, you can specify multiple profiles in @Profile by listing them as an array, like @Profile({"dev", "test"}). The bean will be created if any one of these profiles is active.

beginner

What happens if no profile is active and a bean is annotated with @Profile("dev")?

The bean will NOT be created because its profile does not match the active profile. Only beans with no profile or matching profiles are created.

beginner

How can @Profile help in real-life application development?

It allows you to define different beans or configurations for environments like development, testing, and production. For example, you can use a mock service in development and a real service in production without changing code.

What does the @Profile("prod") annotation do on a Spring bean?

A Disables the bean permanently

B Creates the bean in all profiles except 'prod'

C Creates the bean only when the 'prod' profile is active

D Creates the bean regardless of profile

The @Profile("prod") annotation ensures the bean is created only when the 'prod' profile is active.

How do you specify multiple profiles in @Profile?

A @Profile("dev,test")

B @Profile({"dev", "test"})

C @Profile("dev" & "test")

D @Profile("dev" | "test")

Multiple profiles are specified as an array: @Profile({"dev", "test"}).

If no profile is active, which beans are created?

A Only beans without any <code>@Profile</code> annotation

B Only beans with <code>@Profile("default")</code>

C All beans regardless of <code>@Profile</code>

D No beans are created

Only beans without any @Profile annotation are created if no profile is active.

How can you activate a profile when running a Spring Boot app from the command line?

A java -jar app.jar -Dspring.profile=dev

B java -jar app.jar -profile dev

C java -jar app.jar --profile=dev

D java -jar app.jar --spring.profiles.active=dev

Use --spring.profiles.active=dev to activate the 'dev' profile.

Why use @Profile instead of if-else checks in code?

A It keeps configuration clean and separate by environment

B It makes the app slower

C It disables beans permanently

D It is required by Spring Boot

@Profile helps keep environment-specific code clean and separate, avoiding cluttered if-else logic.

Explain how @Profile helps manage different environments in a Spring Boot application.

Think about how you might use different settings or services in development versus production.

Describe the steps to create and activate a Spring bean only for the 'test' environment using @Profile.

Consider both the bean code and how to run the app with the profile active.