@Profile for environment-specific beans in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What bean is loaded with active profile 'dev'?

Given these two Spring beans with @Profile annotations, which bean will be loaded when the active profile is set to 'dev'?

Spring Boot

import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Component;

@Component
@Profile("dev")
public class DevService {
    public String getName() { return "Development Service"; }
}

@Component
@Profile("prod")
public class ProdService {
    public String getName() { return "Production Service"; }
}

A Both DevService and ProdService beans are loaded.

B ProdService bean is loaded and DevService is ignored.

C DevService bean is loaded and ProdService is ignored.

D No beans are loaded because profiles conflict.

💡 Hint

Think about how @Profile controls bean loading based on active profiles.

The @Profile annotation tells Spring to load a bean only if the specified profile is active. Since the active profile is 'dev', only the DevService bean is loaded. The ProdService bean is ignored because its profile 'prod' is not active.

📝 Syntax

intermediate

Which @Profile annotation syntax is correct?

Which option shows the correct way to use @Profile to specify multiple profiles for a bean in Spring Boot?

A @Profile(dev | test)

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

C @Profile(dev, test)

D @Profile("dev, test")

💡 Hint

Check how arrays are passed in Java annotations.

The correct syntax to specify multiple profiles is to pass an array of strings: @Profile({"dev", "test"}). Other options are either invalid Java syntax or incorrect usage.

🔧 Debug

advanced

Why does this bean not load despite active profile?

Given this bean definition and active profile 'prod', why does Spring fail to load the bean?

Spring Boot

import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Component;

@Component
@Profile("production")
public class PaymentService {
    // service code
}

A Because the active profile is 'prod' but the bean is annotated with 'production'.

B Because @Component is missing.

C Because the class is not public.

D Because @Profile cannot be used on classes.

💡 Hint

Check if the profile names match exactly.

The active profile is 'prod' but the bean is annotated with @Profile("production"), which does not match. Profile names must match exactly for the bean to load.

❓ state_output

advanced

What is the output when no active profile is set?

Consider these two beans with @Profile annotations. What happens if no active profile is set in the Spring Boot application?

Spring Boot

import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Component;

@Component
@Profile("dev")
public class DevConfig {
    public String getConfig() { return "Dev Config"; }
}

@Component
@Profile("prod")
public class ProdConfig {
    public String getConfig() { return "Prod Config"; }
}

A Only ProdConfig bean is loaded by default.

B Both DevConfig and ProdConfig beans are loaded.

C Only DevConfig bean is loaded by default.

D Neither DevConfig nor ProdConfig beans are loaded.

💡 Hint

Think about what happens when no profile is active and beans require profiles.

Beans annotated with @Profile are only loaded if their profile is active. If no profile is active, none of these beans load.

🧠 Conceptual

expert

How to load a bean for all profiles except 'test'?

Which @Profile expression correctly loads a bean for all profiles except 'test' in Spring Boot?

A @Profile("!test")

B @Profile("all & !test")

C @Profile("!test") and @Profile("*")

D @Profile("!test") and @Profile("default")

💡 Hint

Spring supports negation in @Profile expressions.

The @Profile annotation supports negation with !. Using @Profile("!test") loads the bean for all profiles except 'test'. Other options are invalid or unsupported syntax.