Java Todo List Manager: Features, Code Samples, and Best Practices

Java Todo List Manager — Build a Simple Task App in 30 Minutes

Goal

Create a minimal, functional Java Todo List Manager (console + file persistence) in ~30 minutes that supports adding, listing, marking complete, deleting, and saving tasks.

Tech stack

• Java 11+ (console app)
• Plain text or JSON file for persistence
• Optional: Maven, JUnit for tests

Project structure

• src/
  • Main.java — CLI entry
  • model/Task.java — Task data
  • storage/TaskStorage.java — load/save tasks
  • service/TaskService.java — business logic
  • util/ConsoleUtils.java — input/output helpers

Data model (Task)

• id: int
• title: String
• description: String (optional)
• createdAt: Instant
• completed: boolean

Features & commands

• add “title” [“description”] — create task
• list [all|active|completed] — show tasks
• done— mark complete
• delete — remove task
• save — persist now (also auto-save on exit)
• help, exit

Minimal implementation outline

1. Parse simple commands in Main loop.
2. Keep tasks in an in-memory List.
3. TaskStorage reads/writes JSON (use Jackson or simple line format).
4. TaskService provides add/list/complete/delete operations.
5. Auto-assign incremental IDs.

Sample JSON format

[ {“id”:1,“title”:“Buy milk”,“description”:“”,“createdAt”:“2026-02-05T12:00:00Z”,“completed”:false} ]

30-minute breakdown

1. 0–5 min: create project, classes, Task model.
2. 5–15 min: implement TaskService and in-memory operations.
3. 15–25 min: implement CLI parsing and commands.
4. 25–30 min: add simple JSON persistence and quick manual test.

Extensions (optional)

• Use SQLite or H2 for persistence
• Add deadlines, priorities, tags
• Provide GUI with JavaFX or Swing
• Sync with cloud (REST API)
• Add unit tests (JUnit) and input validation

Quick code snippet — adding a task (conceptual)

java
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Task addTask(String title, String description) {
  Task t = new Task(nextId++, title, description, Instant.now(), false);
  tasks.add(t);
  return t;
}

Tips

• Keep CLI parsing simple (split on space, accept quoted strings).
• Persist after each change for safety.
• Use UUIDs if concurrent runs possible.