POM.xml and dependencies in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Dependency Scope in POM.xml

In a Spring Boot project, what is the effect of setting a dependency's scope to provided in the POM.xml?

A The dependency is included in the final build artifact and available at runtime.

B The dependency is only available during compilation but not included in the final artifact.

C The dependency is excluded from compilation and runtime but used for testing only.

D The dependency is downloaded but never used in the project.

💡 Hint

Think about dependencies provided by the runtime environment like a servlet container.

Dependencies with provided scope are needed to compile the project but are expected to be supplied by the runtime environment, so they are not packaged in the final artifact.

❓ component_behavior

intermediate

Effect of Missing Spring Boot Starter Dependency

What happens if you omit the spring-boot-starter-web dependency in your Spring Boot POM.xml but try to create a REST controller?

A The application starts normally but REST endpoints return 404 errors.

B The application starts and REST endpoints work without issues.

C The application fails to start due to missing web server classes.

D The application starts but logs warnings about missing dependencies.

💡 Hint

Consider what the starter web dependency provides.

The spring-boot-starter-web includes embedded Tomcat and Spring MVC. Without it, the app lacks web server classes and fails to start.

📝 Syntax

advanced

Identify the Correct Dependency Declaration

Which POM.xml dependency snippet correctly adds the Spring Boot Starter Data JPA dependency?

A

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

B

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-data-jpa</artifactId>
</dependency>

C

<dependency>
  <groupId>springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

D

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-jpa</artifactId>
  <version>2.7.0</version>
</dependency>

💡 Hint

Check groupId spelling and if version is needed explicitly.

Spring Boot manages versions for starters, so version tag is optional if using parent POM. GroupId must be exactly org.springframework.boot.

🔧 Debug

advanced

Diagnose Dependency Conflict in POM.xml

You added two dependencies: spring-boot-starter-web and spring-boot-starter-webflux. Your app fails to start with a bean creation error. What is the likely cause?

A Both starters provide conflicting web server implementations causing bean conflicts.

B You forgot to add <code>spring-boot-starter-data-jpa</code> dependency.

C The POM.xml is missing the <code>spring-boot-maven-plugin</code>.

D The Java version is incompatible with Spring Boot starters.

💡 Hint

Think about the difference between traditional MVC and reactive web frameworks.

spring-boot-starter-web uses Spring MVC, while spring-boot-starter-webflux uses reactive programming. Including both causes conflicts in web server beans.

❓ state_output

expert

Resulting Dependency Tree Size

If your Spring Boot POM.xml includes only spring-boot-starter-web and spring-boot-starter-data-jpa, approximately how many direct and transitive dependencies will Maven download?

A About 10 dependencies total

B About 30 dependencies total

C More than 100 dependencies total

D About 60 dependencies total

💡 Hint

Consider that starters bring many libraries transitively.

Each Spring Boot starter pulls many dependencies transitively. Together, these two starters typically bring around 60 dependencies.