Test profiles and configuration in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the active profile output?

Given a Spring Boot application with two profiles dev and prod, and the following configuration:

application.properties:
spring.profiles.active=dev

application-dev.properties:
app.message=Development Mode

application-prod.properties:
app.message=Production Mode

@Component
public class MessagePrinter {
  @Value("${app.message}")
  private String message;

  public String getMessage() {
    return message;
  }
}

What will getMessage() return when the application runs?

A Development Mode

B Production Mode

C app.message

D null

💡 Hint

Check which profile is active in application.properties.

The active profile is set to 'dev', so Spring loads application-dev.properties. The app.message value is 'Development Mode'.

📝 Syntax

intermediate

Which configuration activates the 'test' profile correctly?

You want to activate the 'test' profile in a Spring Boot application. Which of the following ways correctly activates the profile?

A Set environment variable SPRING_PROFILES_ACTIVE=test

B Add <code>spring.profiles.active=test</code> in <code>application-test.properties</code>

C Add <code>@Profile("test")</code> on the main application class

D Set <code>spring.profiles.include=test</code> in <code>application.properties</code>

💡 Hint

Activating a profile means telling Spring which profile to use when starting.

Setting the environment variable SPRING_PROFILES_ACTIVE=test activates the 'test' profile globally. Adding the property inside application-test.properties does not activate it by itself.

🔧 Debug

advanced

Why does the bean not load for 'prod' profile?

Consider this Spring Boot bean:

@Component
@Profile("prod")
public class ProdService {
  // service code
}

When running with the 'dev' profile active, the application fails to find ProdService and throws a NoSuchBeanDefinitionException. Why?

A Because @Profile only works on configuration classes, not components

B Because the bean class is missing the @Service annotation

C Because the 'prod' profile is not active, so the bean is not created

D Because the bean requires a constructor argument that is missing

💡 Hint

Check which profile is active and how @Profile works.

The @Profile("prod") annotation means the bean is only created when the 'prod' profile is active. With 'dev' active, Spring skips this bean.

❓ state_output

advanced

What is the value of 'timeout' after loading profiles?

Given these property files:

application.properties:
timeout=30

application-dev.properties:
timeout=10

application-prod.properties:
timeout=60

And the active profile is set to 'prod'. What is the value of timeout injected by @Value("${timeout}")?

A 10

B 30

C null

D 60

💡 Hint

Profile-specific properties override default properties.

The 'prod' profile is active, so application-prod.properties overrides timeout to 60.

🧠 Conceptual

expert

How does Spring Boot resolve multiple active profiles with conflicting properties?

If you set multiple active profiles like spring.profiles.active=dev,prod and both profiles define the same property app.mode with different values, which value does Spring Boot use?

A The value from the first profile listed in <code>spring.profiles.active</code> is used

B The value from the last profile listed in <code>spring.profiles.active</code> is used

C Spring Boot throws an error due to conflicting properties

D Spring Boot merges both values into a list

💡 Hint

Think about the order Spring Boot loads profile properties.

Spring Boot loads profiles in order and later profiles override earlier ones. So the last profile's property wins.