Maven dependency 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 1. Compile Scope 2. Provided Scope 3. Runtime Scope 4. Test Scope 5. System Scope 6. Import Scope 7. Transitivity Resolution
Maven dependency scope – compile
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 dependency scope – provided
Maven dependency 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 dependency scope – runtime
Dependencies with
maven dependency 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 dependency scope – test
Dependencies with maven dependency 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 dependency scope – system
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 dependency scope – import
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 > |
Maven dependency 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 maven transitive dependencies 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.
Dependency | compile | provided | runtime | test |
compile | compile | – | runtime | – |
provided | provided | – | provided | – |
runtime | runtime | – | runtime | – |
test | test | – | test | – |
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