Difference between maven scope compile and provided for JAR packaging – Dev

The best answers to the question “Difference between maven scope compile and provided for JAR packaging” in the category Dev.

QUESTION:

What is the difference between the maven scope compile and provided when artifact is built as a JAR? If it was WAR, I’d understand – the artifact would be included or not in WEB-INF/lib. But in case of a JAR it doesn’t matter – dependencies aren’t included. They have to be on classpath when their scope is compile or provided. I know that provided dependencies aren’t transitive – but is it only one difference?

ANSWER:

Compile means that you need the JAR for compiling and running the app. For a web application, as an example, the JAR will be placed in the WEB-INF/lib directory.

Provided means that you need the JAR for compiling, but at run time there is already a JAR provided by the environment so you don’t need it packaged with your app. For a web app, this means that the JAR file will not be placed into the WEB-INF/lib directory.

For a web app, if the app server already provides the JAR (or its functionality), then use “provided” otherwise use “compile”.

Here is the reference.

ANSWER:

From the Maven Doc:

  • compile

    This is the default scope, used if none is specified. Compile
    dependencies are available in all classpaths of a project.
    Furthermore, those dependencies are propagated to dependent projects.

  • provided

    This is much like compile, but indicates you expect the JDK or a
    container to provide the dependency at runtime. For example, when
    building a web application for the Java Enterprise Edition, you would
    set the dependency on the Servlet API and related Java EE APIs to
    scope provided because the web container provides those classes. This
    scope is only available on the compilation and test classpath, and is
    not transitive.

Recap:

  • dependencies are not transitive (as you mentioned)
  • provided scope is only available on the compilation and test classpath, whereas compile scope is available in all classpaths.
  • provided dependencies are not packaged

ANSWER:

  • compile

Make available into class path, don’t add this dependency into final jar if it is normal jar; but add this jar into jar if final jar is a single jar (for example, executable jar)

  • provided

Dependency will be available at run time environment so don’t add this dependency in any case; even not in single jar (i.e. executable jar etc)

ANSWER:

If you’re planning to generate a single JAR file with all of its dependencies (the typical xxxx-all.jar), then provided scope matters, because the classes inside this scope won’t be package in the resulting JAR.

See maven-assembly-plugin for more information