Address Book (Level 3)
This is a desktop Address Book application. It has a GUI but most of the user interactions happen using a CLI (Command Line Interface).
It is a Java sample application intended for students learning Software Engineering while using Java as the main programming language.
It is written in OOP fashion. It provides a reasonably well-written code example that is significantly bigger (around 6 KLoC)than what students usually write in beginner-level SE modules.