Health endpoint customization in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable the health endpoint in Spring Boot.

Spring Boot

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.[1](args);
    }
}

Drag options to blanks, or click blank then click option'

Alaunch

Bstart

Crun

Dexecute

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' or 'launch' instead of 'run' causes errors.

The SpringApplication.run method starts the Spring Boot application.

2fill in blank

medium

Complete the code to expose the health endpoint in application.properties.

Spring Boot

management.endpoint.health.[1]=true

Drag options to blanks, or click blank then click option'

Aenabled

Bshow

Cexpose

Dactivate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'expose' or 'show' instead of 'enabled' will not work.

The property 'management.endpoint.health.enabled' enables the health endpoint.

3fill in blank

hard

Fix the error in this custom health indicator class by completing the missing annotation.

Spring Boot

import org.springframework.boot.actuate.health.Health;
import org.springframework.boot.actuate.health.HealthIndicator;
import org.springframework.stereotype.[1];

@[1]
public class CustomHealthIndicator implements HealthIndicator {
    @Override
    public Health health() {
        return Health.up().withDetail("status", "All systems go").build();
    }
}

Drag options to blanks, or click blank then click option'

AService

BController

CRepository

DComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Service or @Controller will not register the health indicator correctly.

The @Component annotation registers the class as a Spring bean so it can be used as a health indicator.

4fill in blank

hard

Fill both blanks to customize the health endpoint path and enable detailed health info.

Spring Boot

management.endpoints.web.path-mapping.health=[1]
management.endpoint.health.show-details=[2]

Drag options to blanks, or click blank then click option'

A/custom-health

Balways

Cnever

D/healthcheck

Attempts:

3 left

💡 Hint

Common Mistakes

Using '/healthcheck' for the path but 'never' for details hides info unintentionally.

Setting the path mapping changes the health endpoint URL, and 'always' shows detailed health info.

5fill in blank

hard

Fill all three blanks to create a custom health indicator that reports DOWN status with a message.

Spring Boot

import org.springframework.boot.actuate.health.Health;
import org.springframework.boot.actuate.health.HealthIndicator;
import org.springframework.stereotype.Component;

@Component
public class CustomDownHealthIndicator implements HealthIndicator {
    @Override
    public Health health() {
        return Health.[1]().withDetail("[2]", "[3]").build();
    }
}

Drag options to blanks, or click blank then click option'

Adown

Berror

CDatabase connection failed

Dup

Attempts:

3 left

💡 Hint

Common Mistakes

Using Health.up() instead of Health.down() gives wrong status.

Health.down() sets the status to DOWN, with a detail key 'error' and a message explaining the problem.

Practice

1. What is the main purpose of customizing the health endpoint in Spring Boot?

easy

A. To automatically restart the application on failure

B. To change the port number of the application

C. To add specific checks that show detailed app status

D. To disable all health checks

Solution

1. Step 1: Understand the health endpoint role

   The health endpoint shows the app's status and can be extended to include custom checks.

2. Step 2: Identify customization purpose

   Customizing allows adding specific checks to provide detailed status beyond default info.

3. Final Answer:

   To add specific checks that show detailed app status -> Option C

4. Quick Check:

   Health endpoint customization = detailed app status [OK]

Hint: Health endpoint customization means adding detailed status checks [OK]

Common Mistakes:

• Thinking it changes app port
• Assuming it disables health checks
• Believing it restarts app automatically

2. Which interface must you implement to create a custom health check in Spring Boot?

easy

A. HealthIndicator

B. HealthCheck

C. HealthService

D. HealthStatus

Solution

1. Step 1: Recall Spring Boot health customization

   Custom health checks require implementing a specific interface.

2. Step 2: Identify correct interface

   The interface to implement is HealthIndicator, which requires overriding health().

3. Final Answer:

   HealthIndicator -> Option A

4. Quick Check:

   Custom health check interface = HealthIndicator [OK]

Hint: Custom health checks need HealthIndicator interface [OK]

Common Mistakes:

• Using HealthCheck instead of HealthIndicator
• Confusing with HealthService or HealthStatus
• Not overriding health() method

3. Given this custom health indicator code, what will the health endpoint show?

public class MyHealth implements HealthIndicator {
  @Override
  public Health health() {
    return Health.up().withDetail("db", "reachable").build();
  }
}

medium

A. {"status":"UP","details":{"db":"reachable"}}

B. {"status":"DOWN","details":{"db":"reachable"}}

C. {"status":"UP"}

D. {"status":"DOWN"}

Solution

1. Step 1: Analyze health() method return

   The method returns Health.up() with a detail key "db" set to "reachable".

2. Step 2: Understand output format

   The health endpoint shows status "UP" and includes the details map with "db":"reachable".

3. Final Answer:

   {"status":"UP","details":{"db":"reachable"}} -> Option A

4. Quick Check:

   Health.up() with details = status UP plus details [OK]

Hint: Health.up() withDetail adds details and sets status UP [OK]

Common Mistakes:

• Confusing UP with DOWN status
• Ignoring details in output
• Assuming default status without details

4. Identify the error in this custom health indicator code:

public class CustomHealth implements HealthIndicator {
  public Health health() {
    return Health.down().withDetails("error", "Database unreachable").build();
  }
}

medium

A. Method should be annotated with @Override

B. withDetails() method does not exist, should be withDetail()

C. Method name should be checkHealth() instead of health()

D. Health.down() cannot be used in custom indicators

Solution

1. Step 1: Check method signature and annotations

   The method correctly named health() matches interface; @Override annotation is optional but recommended.

2. Step 2: Verify method calls on Health builder

   The method withDetails() does not exist; correct method is withDetail() for adding one detail.

3. Final Answer:

   withDetails() method does not exist, should be withDetail() -> Option B

4. Quick Check:

   Use withDetail() to add single detail [OK]

Hint: Use withDetail() not withDetails() to add details [OK]

Common Mistakes:

• Missing @Override annotation (not error but best practice)
• Wrong method name instead of health()
• Thinking Health.down() is invalid

5. You want to customize the health endpoint to show "UP" only if both database and cache are reachable. Which approach correctly implements this logic?

hard

A. Use two separate HealthIndicator classes without combining results

B. Return Health.up() always and add details for database and cache status

C. Return Health.down() always and ignore individual checks

D. Return Health.up() if both checks pass; else Health.down() with details for each failure

Solution

1. Step 1: Understand combined health logic

   The health status should be UP only if both database and cache are reachable; otherwise DOWN.

2. Step 2: Implement conditional return with details

   Return Health.up() if both pass; else return Health.down() and include details explaining which failed.

3. Final Answer:

   Return Health.up() if both checks pass; else Health.down() with details for each failure -> Option D

4. Quick Check:

   Combined checks control status UP or DOWN with details [OK]

Hint: Return UP only if all checks pass; else DOWN with failure details [OK]

Common Mistakes:

• Returning UP regardless of failures
• Ignoring combined status logic
• Splitting checks without combining results