Understanding MapStruct Dependency Scope in a Maven Project

What is the appropriate dependency scope for MapStruct in a Maven project?

<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct</artifactId>
    <version>1.4.2.Final</version>
    <scope>compile</scope>
</dependency>

MapStruct is a powerful code generator that simplifies the implementation of mappings between Java bean types. When integrating MapStruct into a Maven project, it's essential to understand the correct configuration of its dependency scope to ensure proper functionality and minimal impact on your project build size.

<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct</artifactId>
    <version>1.4.2.Final</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct-processor</artifactId>
    <version>1.4.2.Final</version>
    <scope>annotationProcessor</scope>
</dependency>

Causes

• Incorrect dependency scope may lead to build issues or runtime errors.
• Certain scopes (like test) may not include MapStruct at runtime, causing unexpected behavior.

Solutions

• Use the 'compile' scope for MapStruct in your Maven dependencies to ensure it is available at both compile and runtime.
• In addition, include the MapStruct processor for code generation under the 'annotationProcessor' scope.

Mistake: Setting MapStruct scope to 'test' instead of 'compile'.

Solution: Ensure that the scope is set to 'compile' for application runtime availability.

Mistake: Neglecting the inclusion of the annotation processor dependency.

Solution: Always include the 'mapstruct-processor' with 'annotationProcessor' scope to generate mappers.