Maven – Dependency Scopes

Maven scope attribute is used to specify the visibility of a dependency, relative to the different lifecycle phases (build, test, runtime etc). Maven provides six scopes i.e. compile, provided, runtime, test, system, and import.

Table of Contents

Compile Scope
Provided Scope
Runtime Scope
Test Scope
System Scope
Import Scope
Transitivity Resolution

Maven Compile Scope

This is maven default scope. Dependencies with compile scope are needed to build, test, and run the project.

Scope compile is to be required in most of the cases to resolve the import statements into your java classes sourcecode.

<dependencies>
	<dependency>
		<groupId>log4j</groupId>
		<artifactId>log4j</artifactId>
		<version>1.2.14</version>
		<!-- You can ommit this because it is default -->
		<scope>compile</scope>
	</dependency>
</dependencies>

Maven Provided Scope

Maven scope provided is used during build and test the project. They are also required to run, but should not exported, because the dependency will be provided by the runtime, for instance, by servlet container or application server.

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>3.0.1</version>
    <scope>provided</scope>
</dependency>

Maven Runtime Scope

Dependencies with maven scope runtime are not needed to build, but are part of the classpath to test and run the project.

<dependency>
    <groupId>com.thoughtworks.xstream</groupId>
    <artifactId>xstream</artifactId>
    <version>1.4.4</version>
    <scope>runtime</scope>
 </dependency>

Maven Test Scope

Dependencies with maven scope test are not needed to build and run the project. They are needed to compile and run the unit tests.

<dependency>
	<groupId>junit</groupId>
	<artifactId>junit</artifactId>
	<version>4.12</version>
	<scope>test</scope>
</dependency>

Maven System Scope

Dependencies with system are similar to ones with scope provided. The only difference is system dependencies are not retrieved from remote repository. They are present under project’s subdirectory and are referred from there. See external dependency for more detail.

<dependency>
  <groupId>extDependency</groupId>
  <artifactId>extDependency</artifactId>
  <scope>system</scope>
  <version>1.0</version>
  <systemPath>${basedir}\war\WEB-INF\lib\extDependency.jar</systemPath>
</dependency>

Maven Import Scope

import scope is only supported on a dependency of type pom in the dependencyManagement section. It indicates the dependency to be replaced with the effective list of dependencies in the specified POM’s dependencyManagement section.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>other.pom.group.id</groupId>
            <artifactId>other-pom-artifact-id</artifactId>
            <version>SNAPSHOT</version>
            <scope>import</scope>
            <type>pom</type>
        </dependency>   
    </dependencies>
</dependencyManagement>

Transitivity Resolution

When you include a maven dependency and it has it’s own other dependencies (i.e. transitive dependencies) then you may want to be clear about the scope of these transitive dependencies as well.

Let’s understand about transitive dependency scope with a simple table. In this table, if a dependency is set to the scope in the left column, transitive dependencies at top row will result in a dependency with the scope listed at their intersection.

Drop me your questions in comments section.

Happy Learning!!