Создана основа ооп для задач

todo/src/main/java/ru/kamask/pet/TodoApp.java

@@ -1,9 +0,0 @@
-package ru.kamask.pet;
-
-public class TodoApp {
-
-    public static void main(String[] args) {
-
-    }
-
-}

todo/src/main/java/ru/kamask/pet/todo/TodoApp.java

@@ -0,0 +1,18 @@
+package ru.kamask.pet.todo;
+
+import ru.kamask.pet.todo.model.SimpleTask;
+
+public class TodoApp {
+
+    @SuppressWarnings("unused")
+    public static void main(String[] args) {
+        var task = new SimpleTask("TodoApp");
+        System.out.println(task);
+
+        task.markAsCompleted();
+
+        var taskData = task.data();
+        System.out.println(taskData);
+    }
+
+}

todo/src/main/java/ru/kamask/pet/todo/model/DataBuilder.java

@@ -0,0 +1,5 @@
+package ru.kamask.pet.todo.model;
+
+public interface DataBuilder<T> {
+    T data();
+}

todo/src/main/java/ru/kamask/pet/todo/model/SimpleTask.java

@@ -0,0 +1,35 @@
+package ru.kamask.pet.todo.model;
+
+public class SimpleTask extends Task implements DataBuilder<SimpleTask.Data> {
+    private boolean done = false;
+
+    public SimpleTask(String title) {
+        super(title);
+    }
+
+    @Override
+    public void markAsCompleted() {
+        done();
+    }
+
+    @Override
+    public boolean isCompleted() {
+        return isDone();
+    }
+
+    void done() {
+        done = true;
+    }
+
+    boolean isDone() {
+        return done;
+    }
+
+    @Override
+    public Data data() {
+        return new Data(id, title, done);
+    }
+
+    record Data(int id, String title, boolean done) {
+    }
+}

todo/src/main/java/ru/kamask/pet/todo/model/Task.java

@@ -0,0 +1,23 @@
+package ru.kamask.pet.todo.model;
+
+public abstract class Task {
+    private static int nextId = 1;
+
+    protected int id;
+    protected String title;
+
+    Task(String title) {
+        this.id = nextId++;
+        this.title = title;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("Задача: id - %d, title: \"%s\"", id, title);
+    }
+
+    abstract public void markAsCompleted();
+
+    abstract public boolean isCompleted();
+
+}