Why monitoring matters in Spring Boot - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable basic actuator endpoints in a Spring Boot application.

Spring Boot

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    [1]
}

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

Aimplementation 'org.springframework.boot:spring-boot-starter-actuator'

Bimplementation 'org.springframework.boot:spring-boot-starter-data-jpa'

Cimplementation 'org.springframework.boot:spring-boot-starter-security'

Dimplementation 'org.springframework.boot:spring-boot-starter-thymeleaf'

Attempts:

3 left

💡 Hint

Common Mistakes

Adding unrelated dependencies like JPA or Thymeleaf instead of actuator.

The actuator starter adds monitoring endpoints to your Spring Boot app.

2fill in blank

medium

Complete the property to expose all actuator endpoints over HTTP.

Spring Boot

management.endpoints.web.exposure.include=[1]

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

Ametrics

Binfo

Chealth

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Exposing only one endpoint like 'health' or 'info' when all are needed.

Using '*' exposes all actuator endpoints for monitoring.

3fill in blank

hard

Fix the error in the code to create a custom health indicator bean.

Spring Boot

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

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

Aup

Bunknown

Cdown

DoutOfService

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'down()' or 'unknown()' which indicate problems.

The 'up()' method indicates the service is healthy.

4fill in blank

hard

Fill both blanks to configure a custom endpoint path and enable it.

Spring Boot

management.endpoints.web.base-path=[1]
management.endpoint.health.enabled=[2]

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

A/monitoring

Btrue

Cfalse

D/api

Attempts:

3 left

💡 Hint

Common Mistakes

Using a path without '/' or disabling the endpoint accidentally.

Setting base-path to '/monitoring' changes the URL prefix.
Enabling health endpoint with 'true' makes it accessible.

5fill in blank

hard

Fill all three blanks to create a REST controller that returns application health status.

Spring Boot

import org.springframework.web.bind.annotation.[1];

@RestController
public class HealthController {

    private final HealthEndpoint healthEndpoint;

    public HealthController(HealthEndpoint healthEndpoint) {
        this.healthEndpoint = healthEndpoint;
    }

    @[2]("/custom-health")
    public Health health() {
        return healthEndpoint.[3]();
    }
}

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

AGetMapping

BRequestMapping

CGetHealth

DGet

Ehealth

Attempts:

3 left

💡 Hint

Common Mistakes

Using RequestMapping without specifying method=GET.

Incorrect method name on HealthEndpoint.

Import and annotate with @GetMapping for a GET endpoint.
Call health() on HealthEndpoint to get the status.

Practice

1. Why is monitoring important in a Spring Boot application?

easy

A. It replaces the need for writing tests.

B. It automatically fixes all bugs without developer input.

C. It slows down the application to prevent overload.

D. It helps detect problems early and keeps the app running smoothly.

Solution

1. Step 1: Understand monitoring purpose

   Monitoring tracks app health and performance in real time.

2. Step 2: Identify benefits in Spring Boot context

   It helps find and fix issues quickly, ensuring smooth operation.

3. Final Answer:

   It helps detect problems early and keeps the app running smoothly. -> Option D

4. Quick Check:

   Monitoring = Early problem detection [OK]

Hint: Monitoring = early problem detection and smooth running [OK]

Common Mistakes:

• Thinking monitoring fixes bugs automatically
• Believing monitoring slows the app down
• Confusing monitoring with testing

2. Which Spring Boot dependency is commonly used to add monitoring features?

easy

A. spring-boot-starter-web

B. spring-boot-starter-actuator

C. spring-boot-starter-data-jpa

D. spring-boot-starter-security

Solution

1. Step 1: Identify monitoring-related starter

   Spring Boot Actuator provides built-in monitoring endpoints.

2. Step 2: Match dependency to monitoring

   spring-boot-starter-actuator adds monitoring and health check features.

3. Final Answer:

   spring-boot-starter-actuator -> Option B

4. Quick Check:

   Actuator = monitoring starter [OK]

Hint: Actuator starter adds monitoring endpoints easily [OK]

Common Mistakes:

• Choosing web starter which is for web apps
• Confusing data-jpa with monitoring
• Selecting security starter unrelated to monitoring

3. Given this Spring Boot Actuator endpoint configuration:
management.endpoints.web.exposure.include=health,info
What will be the output when accessing /actuator/health?

medium

A. {"status":"DOWN"}

B. {"error":"Endpoint not found"}

C. {"status":"UP"}

D. {"info":"No data"}

Solution

1. Step 1: Check exposed endpoints

   Only 'health' and 'info' endpoints are exposed via web.

2. Step 2: Understand default health output

   By default, health endpoint returns {"status":"UP"} if app is running well.

3. Final Answer:

   {"status":"UP"} -> Option C

4. Quick Check:

   Health endpoint = {"status":"UP"} when healthy [OK]

Hint: Health endpoint shows status UP if app is healthy [OK]

Common Mistakes:

• Expecting error when endpoint is exposed
• Confusing info endpoint output with health
• Assuming status DOWN without failure

4. You added Spring Boot Actuator but /actuator/health returns 404 error. What is the likely cause?

medium

A. The endpoint is disabled or not exposed in configuration.

B. The URL path is incorrect; it should be /health.

C. The application is not running.

D. Actuator dependency is missing in the project.

Solution

1. Step 1: Confirm Actuator dependency presence

   If dependency was missing, app wouldn't compile or actuator endpoints wouldn't exist.

2. Step 2: Check endpoint exposure settings

   By default, some actuator endpoints are disabled or not exposed over web, causing 404.

3. Final Answer:

   The endpoint is disabled or not exposed in configuration. -> Option A

4. Quick Check:

   Disabled endpoint = 404 error [OK]

Hint: Check actuator endpoint exposure settings if 404 occurs [OK]

Common Mistakes:

• Assuming missing dependency without checking config
• Thinking app not running causes 404 instead of connection error
• Using wrong URL path for actuator endpoints

5. You want to monitor custom metrics in your Spring Boot app. Which approach best fits this need?

hard

A. Add custom metrics using Micrometer and expose them via Actuator endpoints.

B. Write logs manually and parse them later for metrics.

C. Use only the default health endpoint without changes.

D. Disable Actuator and rely on external monitoring tools only.

Solution

1. Step 1: Understand custom metrics requirement

   Custom metrics need to be collected and exposed in a structured way.

2. Step 2: Identify Spring Boot recommended method

   Micrometer integrates with Actuator to add and expose custom metrics easily.

3. Final Answer:

   Add custom metrics using Micrometer and expose them via Actuator endpoints. -> Option A

4. Quick Check:

   Micrometer + Actuator = custom metrics [OK]

Hint: Use Micrometer with Actuator for custom metrics [OK]

Common Mistakes:

• Relying only on logs for metrics
• Using default health endpoint for custom metrics
• Disabling Actuator loses monitoring benefits