How to download all Maven dependencies into a folder

In this article we’ll look at how to use Maven to download all of your Java project’s dependencies, like libraries and frameworks, and save them into a specific folder.

Normally, you don’t need to download your dependencies explicitly! Maven automatically downloads your project’s dependencies, whenever you run a build. (So you can ignore this post.)

So why might you need to download dependencies? Well, you might need to do this if…

• You want to run your project (and its dependencies) on another machine which doesn’t have internet access

• You want to debug a library, so you want a local copy

• You simply like collecting jars

If this sounds like you, read on.

Steps to download all dependencies

When you want to do something in Maven, you usually need a plugin. Most features in Maven – like compiling code, running tests and downloading dependencies – are implemented inside a plugin.

To download dependencies, you can use the Maven Dependency Plugin.

Download dependencies (without building your project)

From the Maven Dependency Plugin, we can use the goal copy-dependencies. It downloads dependencies from a repository (usually the “main” online repository, Maven Central) to our local project folder.

You can execute this goal separately, without building your project.

Here’s how to do it:

1. In your project’s pom.xml, make sure that you’ve added all the dependencies you want to use.

2. Drop to a terminal in your project folder (where your pom.xml is located).

3. Run this command to execute the goal copy-dependencies, which starts downloading dependencies:

   mvn dependency:copy-dependencies
   

4. Maven Dependency Plugin will download dependencies (for example, JAR files) into the folder target/dependency.

Afterwards, you will see that the files have been downloaded:

$ ls -al target/dependency
total 63676
drwxr-xr-x. 2 tdonohue tdonohue    16384 Jun 26 10:46 .
drwxr-xr-x. 7 tdonohue tdonohue     4096 Jun 26 10:46 ..
-rw-r--r--. 1 tdonohue tdonohue   364206 Jun 26 10:46 aesh-2.6.jar
-rw-r--r--. 1 tdonohue tdonohue     6806 Jun 26 10:46 apiguardian-api-1.1.2.jar
-rw-r--r--. 1 tdonohue tdonohue   199943 Jun 26 10:46 arc-2.9.2.Final.jar
-rw-r--r--. 1 tdonohue tdonohue   122176 Jun 26 10:46 asm-9.3.jar
....

And that’s pretty much it.

Download dependencies to a specific location

Want to download to a different location? No problem.

The Maven Dependency Plugin copy-dependency goal saves files to target/dependency by default. But you can change the behaviour, by setting the property outputDirectory.

Here’s an example:

mvn dependency:copy-dependencies -DoutputDirectory=/mydeps

(See how we use -D to set a property.)

Now Maven will download the artifacts to the /mydeps directory.

How does it work?

Like most features in Maven, this is made possible by a plugin, the Maven Dependency Plugin. The plugin helps you to manage your project’s dependencies:

About the plugin:

The plugin analyses the dependencies in your project, and copies dependencies from Maven Central (or the repository you have configured).

There are lots of other plugins for Maven, too - see the list.

Wrapping up

We’ve seen how you can use the Maven Dependency Plugin to download all of your project’s dependencies (JAR files) into a single folder.

We activate this plugin using the dependency: prefix, and then choose the goal to execute. In our case, we use the copy-dependencies goal.

If you want to check out what else the plugin can do, see the documentation.

Happy building!