Spring Boot - Fundamentals - Guided Exercise - TaskTrackr – Build a Spring Boot CLI To-Do Manager

[akash-coded]

This exercise will:

• Reinforce core Java concepts (OOP, collections, lambdas)

• Show Spring Boot in CLI mode (no REST controllers yet)

• Introduce Spring Boot structure, lifecycle, @Component, @Service, and dependency injection

---

🧪 Exercise: TaskTrackr – Build a Spring Boot CLI To-Do Manager

---

📖 Project Summary

You’re building TaskTrackr, a simple CLI-based task manager using Spring Boot. You’ll:

• Create a Spring Boot CLI app

• Add services using @Component and @Service

• Use Java concepts like OOP, ArrayList, lambdas

• Inject dependencies using @Autowired

• Build step-by-step while understanding how Spring Boot wires everything

---

🛠 Step-by-Step Instructions

---

✅ STEP 1: Generate a Spring Boot CLI Project

Go to 👉 https://start.spring.io

• Project: Maven

• Language: Java

• Spring Boot: Keep default (latest stable)

• Group: com.lambdamart

• Artifact: tasktrackr

• Name: tasktrackr

• Description: Spring Boot CLI To-Do Manager

• Packaging: Jar

• Java: 17+

📦 No dependencies yet!
Unzip and import the project into Eclipse IDE.

---

🧠 Hidden Pro Tip

🔍 When importing in Eclipse:
File → Import → Maven → Existing Maven Projects → Select root dir → Finish.

---

✅ STEP 2: Understand the Spring Boot Skeleton

Explore your project:

src
└── main
    └── java
        └── com.lambdamart.tasktrackr
            ├── TasktrackrApplication.java  ← main runner

✍️ Rename the class to TaskTrackrApp
✅ Update the filename and class name accordingly.

---

✅ STEP 3: Create a Task Class (Java POJO)

📄 Task.java

package com.lambdamart.tasktrackr.model;
public class Task {

private int id;

private String description;

private boolean completed;
public Task(int id, String description) {
    this.id = id;
    this.description = description;
    this.completed = false;
}

// TODO: Add getters and setters

@Override
public String toString() {
    return "[" + id + "] " + description + (completed ? " ✅" : " ❌");
}

}

---

✅ STEP 4: Create a Component to Manage Tasks

📄 TaskService.java

package com.lambdamart.tasktrackr.service;
import com.lambdamart.tasktrackr.model.Task;

import org.springframework.stereotype.Service;

import java.util.*;
@Service

public class TaskService {
private List<Task> tasks = new ArrayList<>();
private int idCounter = 1;

public void addTask(String description) {
    tasks.add(new Task(idCounter++, description));
    System.out.println("📌 Task added.");
}

public void listTasks() {
    if (tasks.isEmpty()) {
        System.out.println("📭 No tasks yet.");
        return;
    }
    tasks.forEach(System.out::println);
}

public void markDone(int id) {
    tasks.stream()
         .filter(t -> t.getId() == id)
         .findFirst()
         .ifPresentOrElse(
             t -> { t.setCompleted(true); System.out.println("✅ Marked as done."); },
             () -> System.out.println("❌ Task not found.")
         );
}

public void removeTask(int id) {
    tasks.removeIf(t -> t.getId() == id);
    System.out.println("🗑️ Task removed.");
}

}

---

💡 Hidden Pro Tip

💉 Annotate classes with @Component, @Service, @Repository so Spring can detect and inject them.
You don't need new – Spring handles the lifecycle!

---

✅ STEP 5: Autowire the Service into Main App

📄 TaskTrackrApp.java

package com.lambdamart.tasktrackr;
import com.lambdamart.tasktrackr.service.TaskService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.boot.CommandLineRunner;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import java.util.Scanner;
@SpringBootApplication

public class TaskTrackrApp implements CommandLineRunner {
@Autowired
private TaskService taskService;

public static void main(String[] args) {
    SpringApplication.run(TaskTrackrApp.class, args);
}

@Override
public void run(String... args) {
    Scanner scanner = new Scanner(System.in);
    String input;

    System.out.println("🎯 Welcome to TaskTrackr!");
    System.out.println("Commands: add <task>, list, done <id>, remove <id>, exit");

    while (true) {
        System.out.print("> ");
        input = scanner.nextLine();

        if (input.startsWith("add ")) {
            taskService.addTask(input.substring(4).trim());
        } else if (input.equals("list")) {
            taskService.listTasks();
        } else if (input.startsWith("done ")) {
            taskService.markDone(Integer.parseInt(input.split(" ")[1]));
        } else if (input.startsWith("remove ")) {
            taskService.removeTask(Integer.parseInt(input.split(" ")[1]));
        } else if (input.equals("exit")) {
            break;
        } else {
            System.out.println("❓ Unknown command.");
        }
    }

    scanner.close();
    System.out.println("👋 Exiting TaskTrackr.");
}

}

---

🧠 Shortcut Tip:

Type sout + Tab in Eclipse to auto-generate System.out.println()
Use Shift + Ctrl + O to auto-import missing packages.

---

🔁 Practice Tasks for Students

🔲 Task 1: Add a method in TaskService to:

• Search for tasks containing a keyword (case-insensitive)

// Write only the method body:
public void search(String keyword) {
    // 🔲 Your code here
}

---

🔲 Task 2: Modify listTasks() to show total task count at the end.

📋 Total Tasks: 5
✅ Completed: 2
❌ Pending: 3

Use Java streams + lambdas.

---

🔲 Task 3: Add a method to delete all completed tasks.

public void clearCompleted() {
    // 🔲 Your code here using removeIf
}

---

🧠 Bonus Challenge

1. Add sorting feature: completed tasks at bottom

2. Save and load tasks using a .txt or .json file

3. Add a Category field to Task and filter by category

---

📘 Spring Boot Concepts Recap

Concept	Example Used
Spring Boot Project	start.spring.io
@SpringBootApplication	Entry point TaskTrackrApp
@service	TaskService
@Autowired	Injecting TaskService
CommandLineRunner	Run logic at startup
Java OOP + List	Task class, ArrayList
Lambda + Streams	listTasks(), markDone()

---

🧾 Deliverables from Students

• ✅ Working Spring Boot CLI app with:

  • add, list, done, remove, exit

• ✅ Extra methods for:

  • search

  • clearCompleted

  • stats summary

• ✅ Use of:

  • @Service, @Autowired

  • List, Stream, removeIf, forEach

---

Want a .docx assignment sheet, Eclipse project starter zip, or auto-check test cases?
Let me know and I’ll generate them.

Absolutely. Here's a **step-by-step, semi-guided, industry-style Spring Boot exercise** designed to be beginner-friendly, yet packed with **hidden pro tips**, **Java practice**, and **Spring Boot essentials**.

This exercise will:

• Reinforce core Java concepts (OOP, collections, lambdas)
• Show Spring Boot in CLI mode (no REST controllers yet)
• Introduce Spring Boot structure, lifecycle, @Component, @Service, and dependency injection
• Let students see the magic of autowiring + beans + clean architecture

---

🧪 Exercise: TaskTrackr – Build a Spring Boot CLI To-Do Manager

---

📖 Project Summary

You’re building TaskTrackr, a simple CLI-based task manager using Spring Boot. You’ll:

• Create a Spring Boot CLI app
• Add services using @Component and @Service
• Use Java concepts like OOP, ArrayList, lambdas
• Inject dependencies using @Autowired
• Build step-by-step while understanding how Spring Boot wires everything

---

🛠 Step-by-Step Instructions

---

✅ STEP 1: Generate a Spring Boot CLI Project

Go to 👉 https://start.spring.io/

• Project: Maven
• Language: Java
• Spring Boot: Keep default (latest stable)
• Group: com.lambdamart
• Artifact: tasktrackr
• Name: tasktrackr
• Description: Spring Boot CLI To-Do Manager
• Packaging: Jar
• Java: 17+

📦 No dependencies yet!
Unzip and import the project into Eclipse IDE.

---

🧠 Hidden Pro Tip

🔍 When importing in Eclipse:
File → Import → Maven → Existing Maven Projects → Select root dir → Finish.

---

✅ STEP 2: Understand the Spring Boot Skeleton

Explore your project:

src
└── main
    └── java
        └── com.lambdamart.tasktrackr
            ├── TasktrackrApplication.java  ← main runner

✍️ Rename the class to TaskTrackrApp
✅ Update the filename and class name accordingly.

---

✅ STEP 3: Create a Task Class (Java POJO)

📄 Task.java

package com.lambdamart.tasktrackr.model;

public class Task {
    private int id;
    private String description;
    private boolean completed;

    public Task(int id, String description) {
        this.id = id;
        this.description = description;
        this.completed = false;
    }

    // TODO: Add getters and setters

    @Override
    public String toString() {
        return "[" + id + "] " + description + (completed ? " ✅" : " ❌");
    }
}

---

✅ STEP 4: Create a Component to Manage Tasks

📄 TaskService.java

package com.lambdamart.tasktrackr.service;

import com.lambdamart.tasktrackr.model.Task;
import org.springframework.stereotype.Service;
import java.util.*;

@Service
public class TaskService {

    private List<Task> tasks = new ArrayList<>();
    private int idCounter = 1;

    public void addTask(String description) {
        tasks.add(new Task(idCounter++, description));
        System.out.println("📌 Task added.");
    }

    public void listTasks() {
        if (tasks.isEmpty()) {
            System.out.println("📭 No tasks yet.");
            return;
        }
        tasks.forEach(System.out::println);
    }

    public void markDone(int id) {
        tasks.stream()
             .filter(t -> t.getId() == id)
             .findFirst()
             .ifPresentOrElse(
                 t -> { t.setCompleted(true); System.out.println("✅ Marked as done."); },
                 () -> System.out.println("❌ Task not found.")
             );
    }

    public void removeTask(int id) {
        tasks.removeIf(t -> t.getId() == id);
        System.out.println("🗑️ Task removed.");
    }
}

---

💡 Hidden Pro Tip

💉 Annotate classes with @Component, @Service, @Repository so Spring can detect and inject them.
You don't need new – Spring handles the lifecycle!

---

✅ STEP 5: Autowire the Service into Main App

📄 TaskTrackrApp.java

package com.lambdamart.tasktrackr;

import com.lambdamart.tasktrackr.service.TaskService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import java.util.Scanner;

@SpringBootApplication
public class TaskTrackrApp implements CommandLineRunner {

    @Autowired
    private TaskService taskService;

    public static void main(String[] args) {
        SpringApplication.run(TaskTrackrApp.class, args);
    }

    @Override
    public void run(String... args) {
        Scanner scanner = new Scanner(System.in);
        String input;

        System.out.println("🎯 Welcome to TaskTrackr!");
        System.out.println("Commands: add <task>, list, done <id>, remove <id>, exit");

        while (true) {
            System.out.print("> ");
            input = scanner.nextLine();

            if (input.startsWith("add ")) {
                taskService.addTask(input.substring(4).trim());
            } else if (input.equals("list")) {
                taskService.listTasks();
            } else if (input.startsWith("done ")) {
                taskService.markDone(Integer.parseInt(input.split(" ")[1]));
            } else if (input.startsWith("remove ")) {
                taskService.removeTask(Integer.parseInt(input.split(" ")[1]));
            } else if (input.equals("exit")) {
                break;
            } else {
                System.out.println("❓ Unknown command.");
            }
        }

        scanner.close();
        System.out.println("👋 Exiting TaskTrackr.");
    }
}

---

🧠 Shortcut Tip:

Type sout + Tab in Eclipse to auto-generate System.out.println()
Use Shift + Ctrl + O to auto-import missing packages.

---

🔁 Practice Tasks for Students

🔲 Task 1: Add a method in TaskService to:

• Search for tasks containing a keyword (case-insensitive)

// Write only the method body:
public void search(String keyword) {
    // 🔲 Your code here
}

---

🔲 Task 2: Modify listTasks() to show total task count at the end.

📋 Total Tasks: 5
✅ Completed: 2
❌ Pending: 3

Use Java streams + lambdas.

---

🔲 Task 3: Add a method to delete all completed tasks.

public void clearCompleted() {
    // 🔲 Your code here using removeIf
}

---

🧠 Bonus Challenge

1. Add sorting feature: completed tasks at bottom
2. Save and load tasks using a .txt or .json file
3. Add a Category field to Task and filter by category

---

📘 Spring Boot Concepts Recap

Concept	Example Used
Spring Boot Project	start.spring.io
@SpringBootApplication	Entry point TaskTrackrApp
@Service	TaskService
@Autowired	Injecting TaskService
CommandLineRunner	Run logic at startup
Java OOP + List	Task class, ArrayList
Lambda + Streams	listTasks(), markDone()

---

🧾 Deliverables from Students

• ✅ Working Spring Boot CLI app with:

  • add, list, done, remove, exit

• ✅ Extra methods for:

  • search
  • clearCompleted
  • stats summary

• ✅ Use of:

  • @Service, @Autowired
  • List, Stream, removeIf, forEach

[Sdey0907]

> ### **Task- TaskTrackr – Build a Spring Boot CLI To-Do Manager_Sayan Dey_Completed**

tasktrackr_SB__Project.zip

[prasetha21-max]

tasktrackr.zip