I am very sure a lot of
times this question might have come to your mind, what exactly the scope is
in our Pom.xml file why to use and what is the purpose of this. In this blog, I
will try my best to answer these questions.
As per official maven
documentation, Scope Tag in maven dependency is used to use to limit the
transitivity of dependency or in simpler terms to define the scope or phase
in which that dependency will actually work.
The <Scope> the element can take six values in our pom.xml file:
Ø Compile
Ø Provided
Ø Runtime
Ø Test
Ø System
Ø Import
Now Let’s look into
more details for all these six Scopes.
Compile
This is the maven
default scope. This dependency is needed for the purpose of build, test and
runs the project.
Compile dependencies
are available in all classpaths of a project. These dependencies are also
transferred to dependent projects.
For e.g, we need the JAR
for compiling and running the web application
Provided
Provided is quite
similar to compile and is used during build and test the project.
This is also required to run, but should not be exported, because the dependency will be provided at the runtime by JDK or a container.
e.g We need JAR for
compiling the project, but at run time there is already a JAR provided by the environment so we don't need it to packaged again with our web application.
RunTime
This dependency is not
required for build or compilation, but is required to test and run our project.
Test
Test are not
needed to build and run the project. They are needed to compile and run
the unit tests.
System
This is similar to
provided and the only difference is system dependencies are not retrieved
from remote repository. They are present under some project’s subdirectory and
are referenced from there.
For e.g some
dependencies we might have created by our own and wanted to use it in our
project.
Import
This scope is
only supported on a dependency of type pom in the dependencyManagement section. Maven 2.0.9 or later replaces pom
with dependencymanagement Section.
