How to use the Maven Optional dependency attribute?

In Maven, you can use the optional attribute to specify if a dependency is considered optional. This means that if the corresponding library cannot be found when importing the dependency, Maven will not throw an error and will instead simply ignore the import of that dependency.

The syntax for using the optional attribute is as follows:

<dependency>
  <groupId>group-id</groupId>
  <artifactId>artifact-id</artifactId>
  <version>version</version>
  <optional>true</optional>
</dependency>

One option is to set the value of the optional element to true or false, with the default being false. If optional is set to true, the dependency is considered optional; if set to false, the dependency is required.

For example, here is a sample using optional dependencies:

<dependencies>
  <dependency>
    <groupId>org.example</groupId>
    <artifactId>example-library</artifactId>
    <version>1.0.0</version>
    <optional>true</optional>
  </dependency>
</dependencies>

In this example, the dependency on example-library is marked as optional. If example-library cannot be found during the project build process, Maven will ignore the inclusion of this dependency and continue with the build.

It’s important to note that the use of optional dependencies should be approached with caution and only used when necessary. This is because optional dependencies may complicate the project’s dependency structure and introduce unstable or incompatible libraries.