“Splitting packages by layers is just like splitting co-workers by profession instead of splitting them into organization teams.”
Imagine this ridiculous situation:
Managers company, Programmers company, Human Resources company and Marketing company, where the Programmers company will only have programmers and no managers, marketeers or human resources;
Packaging stuff together by what it is, and not by what it does, will only make you jump 10 times to the place you are looking for.
Gains and Benefits
- By looking at the structure you can already tell what the app is all about (figure 1);
- Higher modularity;
- Easier code navigation;
- Higher level of abstraction;
- Separates both features and layers;
- More readable and maintainable structure;
- More cohesion;
- Much easier to scale;
- Less chance to accidentally modify unrelated classes or files;
- Much easier to add or remove application features;
- And much more reusable modules.