Using the Java platform’s ServiceLoader class to retrieve JPMS provider implementations

So far, we have configured the module descriptor of the Application and Framework hexagon modules. We have refactored the input adapters so that they only depend on the abstractions provided by use case interfaces. But how can we retrieve the concrete instances that implement those use case interfaces? That’s exactly what the ServiceLoader class does.

ServiceLoader is not a new class made solely to support JPMS features. Instead, ServiceLoader has been present in Java since version 1.6. From Java 9 onward, this class was enhanced to work with the Java module’s services. It relies on the configuration provided by the module descriptor to find implementations for a given service provider interface.

To illustrate how we can use ServiceLoader, let’s update the FrameworkTestData test class by creating a method called loadPortsAndUseCases. This method uses ServiceLoader...