We have an internal java application (let's call it com.example.framework) acting as a kind of framework in the sense of being extensible through plugins. These plugins can serve various purposes. As an example, there will be a plugin for the support of the differnt database providers, e.g., MysqlPlugin, OraclePlugin and MssqlPlugin. On the other hand their might be support for exchange formats such as JSON or XML, etc.
The framework application is developed as a seperate multi-module java project with the parent group id com.example.framework having the API/SPI as a distinct child module. Therefore, the plugins have this api-module as a dependecy called com.example.framework.api, which works perfectly fine. Idealy, each plugin will have its own artifact under a group called com.example.framework.plugins such that I will only have those plugins installed that are really needed.
To ease the developer experience, I would like to group plugins of similar functionality, which even might want to share a bit of code together to a git project while keeping some special ones alone. Now I wonder what the best way of structuring this in the maven system is.
The best solution I could find is to also use the multi-module approach for grouped plugin projects to achieve splitted artifacts while being able to share code between two plugins. However, I am still confused about the groupId and version of the parent:
The naming convention of maven suggests to use a unique groupId for each project. This would mean to introduce another depth of naming, e.g. com.example.framework.plugins.sql.mysql, which would be inconvenient, since the name of a plugin is no longer sufficient to derive the full module name (with the a-priori knowledge of the common package name com.example.framework.plugins). So I wonder, whether the purpose of the convention is soley to avoid possible duplicates by design? Since I control the namespace and all plugins, I would make sure that there are no conflicts.
If I were to remove the intermediate name layer and thus have multiple parent poms with the same groupId, what problems could arise? Since plugins would not even share versions, the parent has no real purpose and also no artifact on its own that could collide, or am I missing anything? Or is my entire structure not ideal and I should adopt some other form? During my research I could not find any similar use-case.
Usually, different related projects share the same groupId. There is no problem in that. The linked Maven page is misleading.