I'm trying to create a framework for plugin/apps, and I think I've settled on using a Service Provider Interface (SPI) in Java to achieve that. The ultimate vision is that people can download plugins (like an app store) and then just drop the jars into a folder, and they'll work with the existing program.
So I have a class PluginInterface that will be my SPI. I want all plugins to implement this class (it has basic methods like doesAccept, handle, etc.). Since 3rd parties will be creating the Service Providers, how can I let them reference this Java interface in their code (so they can implement it), without actually giving them the source code of the main application?
Create two JARs api and impl where you put your application in the impl and put whatever the code you need to share with third party developer in api.
Example: jaxb-api.jar and jaxb-impl.jar