Maven Dependency Scopes

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Introduction

When adding dependencies in a Maven build, every dependency has a scope, which controls how it is consumed.

 <dependency>
    <groupId>somegroupid</groupId>
    <artifactId>someartifactid</artifactId>
    <version>1.0</version>
    <scope>scopevaluegoeshere</scope>
 </dependency>

Background

To make sure we understand Maven scopes, let’s discuss some related terms:

Compilation

Compilation is when the Maven build for this project uses the Java compiler to create byte code from the application’s Java source code.

Testing

A Maven build for a project has 2 possible testing phases within that project’s build lifecycle:

Unit Testing
Integration Testing

Runtime

This is the behavior used when this Java project is being executed.

Transitive Dependencies

If this Java project is a dependency in another Java project, then certain dependencies may be carried forward as transitive dependencies in that second project. Just by including this Java project as a dependency, then transitive dependencies are also implicitly included.

Scopes

Maven dependencies can carry the following scope values:

Scope value	Used During Build – Compilation	Used During Build – Testing	Available In the Runtime Classpath	Included as Transitive Dependency, If Applicable	Comments
compile (default)	Y	Y	Y	Y	The default scope, when omitted.
provided	Y	Y			Can be looked up in the Maven repository during the build. Should be provided by the server used for the deployment when executing.
runtime		Y	Y		Not needed during compilation, but it is needed for runtime execution. Therefore, also included for test execution.
test		Y			Test frameworks or libraries only used during testing.
~~system~~	Y				DEPRECATED – DO NOT USE: Similar to provided, but build configuration must provide a path to a jar file. Not looked up in the Maven repository. Also expects the systemPath element, such as: <systemPath>${java.home}/../lib/tools.jar</systemPath>
import	?	?	?	?	Used for importing other poms, often called Bill of Material (BOM) poms. Not directly transitive, but imported dependencies from that pom may be.

Y – Yes
? – Depends upon the scope of the imported dependencies inside of the imported pom.

Summary

Maven dependencies can be controlled with a scope value, indicating how they should be used in this Java project’s build and whether or not they should be included in any projects that depend upon this project (AKA as a transitive dependency).

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