Main by whereisalemon-lab · Pull Request #2023 · mate-academy/jv-lottery

whereisalemon-lab · 2026-02-26T15:53:28Z

No description provided.

mateacademy-ai-mentor

Review Summary

Good job on implementing the core logic for the lottery! However, a few changes are needed because there is a critical issue that prevents the code from compiling, along with several violations of the project's checklist.

The main problem is that the Main class is declared as public inside Lottery.java. In Java, a file can only contain one top-level public class, and its name must match the filename. This causes a compilation error.

Additionally, please address these checklist violations:

The Color enum and the ColorSupplier, Ball, and Lottery classes are missing required access modifiers. [CHECKLIST ITEM #7]
The number 3 used in the for loop is a magic number and should be a named constant. [CHECKLIST ITEM #9]
The getRandomBall() method uses temporary variables instead of returning the new Ball object directly. [CHECKLIST ITEM #2]

Once you fix these issues, your solution will be ready!

✨ Please rate this review in the Platform's notification center¹. I will be grateful for your feedback! ✨

Important

Fix the issues, commit the changes, and then re-request my review using the Re-request review button² in the Reviewers tab.

Tip

If you have any comments about this review, please leave a message in the Add a comment section below and mention me with the @mateacademy-ai-mentor tag³.
I will read your message during my next review of your pull request. Please do not reply directly to my comments, as that feature is not supported yet.

Caution

Do not close the pull request until the review is complete. Closing it early can lead to unexpected behavior and disrupt the review process.

mateacademy-ai-mentor · 2026-02-26T15:55:14Z

Lottery.java

@@ -0,0 +1,55 @@
+import java.util.Random;
+enum Color {


This violates checklist item #7: 'Classes, fields, constructors, methods must have access modifiers'. Please add an explicit access modifier to this enum, for example public.

mateacademy-ai-mentor · 2026-02-26T15:55:14Z

Lottery.java

+    GREEN, BLUE, PURPLE, WHITE, BLACK, YELLOW, ORANGE
+}
+
+class ColorSupplier {


This violates checklist item #7: 'Classes, fields, constructors, methods must have access modifiers'. Please add an explicit access modifier to this class.

mateacademy-ai-mentor · 2026-02-26T15:55:14Z

Lottery.java

+    }
+}
+
+class Ball {


This violates checklist item #7: 'Classes, fields, constructors, methods must have access modifiers'. Please add an explicit access modifier to this class.

mateacademy-ai-mentor · 2026-02-26T15:55:14Z

Lottery.java

+
+}
+
+class Lottery {


This violates checklist item #7: 'Classes, fields, constructors, methods must have access modifiers'. As the file is named Lottery.java, this class should be declared as public.

mateacademy-ai-mentor · 2026-02-26T15:55:14Z

Lottery.java

+        String color = colorSupplier.getRandomColor();
+
+        int number = random.nextInt(MAX_NUMBER + 1); 
+        return new Ball(color, number);


This violates checklist item #2: 'Don't create temporary variables if you can directly return value from the method'. The values for color and number can be generated directly within the new Ball(...) constructor call and returned in a single statement.

mateacademy-ai-mentor · 2026-02-26T15:55:14Z

Lottery.java

+    }
+
+}
+    public class Main {


A Java source file can have at most one top-level public class, and its name must match the filename. Since this file is named Lottery.java, the Main class cannot be declared as public here.

mateacademy-ai-mentor · 2026-02-26T15:55:14Z

Lottery.java

+
+        System.out.println("Drawing 3 balls");
+
+        for (int i = 1; i <= 3; i++) {


This violates checklist item #9: 'All magic numbers in your code should be constants'. The number 3 here is a magic number. It's better to declare it as a named constant, for example, private static final int BALLS_TO_DRAW = 3;.

mateacademy-ai-mentor

Review Summary

I am requesting changes because there are a couple of critical structural issues that prevent your code from compiling. It's great that you've fixed the previous issues like adding constants and access modifiers!

However, the code currently has two main problems:

Compilation Error: The public class name LotterySystem does not match the filename Lottery.java. In Java, a file can only have one public class, and its name must exactly match the file's name.
Incorrect Structure: All classes (Lottery, Ball, ColorSupplier) and the Color enum are nested as static members inside a single file. The intended design is to have each of these in its own separate file (e.g., Ball.java, Lottery.java, Color.java).

Please address these by moving each class and enum to its own file and ensuring the public class name matches the filename. You're very close to a great solution!

✨ Please rate this review in the Platform's notification center¹. I will be grateful for your feedback! ✨

Important

Fix the issues, commit the changes, and then re-request my review using the Re-request review button² in the Reviewers tab.

Tip

If you have any comments about this review, please leave a message in the Add a comment section below and mention me with the @mateacademy-ai-mentor tag³.
I will read your message during my next review of your pull request. Please do not reply directly to my comments, as that feature is not supported yet.

Caution

Do not close the pull request until the review is complete. Closing it early can lead to unexpected behavior and disrupt the review process.

mateacademy-ai-mentor · 2026-02-26T16:02:56Z

Lottery.java

@@ -0,0 +1,54 @@
+import java.util.Random;
+
+public class LotterySystem {


The public class name LotterySystem must match the filename Lottery.java to avoid a compilation error. The intended structure for this task is to have each class (Lottery, Ball, ColorSupplier, etc.) and the enum in their own separate .java files.

mateacademy-ai-mentor · 2026-02-26T16:02:56Z

Lottery.java

+        GREEN, BLUE, PURPLE, WHITE, BLACK, YELLOW, ORANGE
+    }
+
+    public static class ColorSupplier {


This violates checklist item #3: 'Don't use static methods in your solution'. While the methods inside are not static (which is correct), the class itself should not be static. The classes ColorSupplier, Ball, and Lottery should be regular top-level classes, each in its own file.

mateacademy-ai-mentor

Review Summary

I am approving this solution as an educational override to help you progress, but it's important to address the structural feedback from the previous review. Great job fixing the filename to match the public class name!

The main issue remains the file structure. In Java, each public class and enum should be in its own separate file (e.g., Ball.java, Color.java). Currently, Color, ColorSupplier, and Ball are all nested inside Lottery.java. Separating them is a fundamental convention that makes code much easier to read and maintain.

Also, the nested Lottery class inside the main Lottery class is very confusing. Its logic should be merged into the main public class Lottery. Correcting these points will also resolve the improper use of static for these classes. Keep up the great work, and focus on applying this structural feedback in your next tasks!

✨ Please rate this review in the Platform's notification center¹. I will be grateful for your feedback! ✨

Rate AI review example ↩

mateacademy-ai-mentor · 2026-02-26T16:17:26Z

Lottery.java

+    public enum Color {
+        GREEN, BLUE, PURPLE, WHITE, BLACK, YELLOW, ORANGE
+    }
+
+    public static class ColorSupplier {
+        private final Random random = new Random();
+
+        public String getRandomColor() {
+            Color[] colors = Color.values();
+            return colors[random.nextInt(colors.length)].name();
+        }
+    }
+
+    public static class Ball {
+        private final String color;
+        private final int number;
+
+        public Ball(String color, int number) {
+            this.color = color;
+            this.number = number;
+        }
+
+        @Override
+        public String toString() {
+            return "Ball: " + color + ", number: " + number;
+        }
+    }
+
+    public static class Lottery {
+        private final ColorSupplier colorSupplier = new ColorSupplier();
+        private final Random random = new Random();
+        private static final int MAX_NUMBER = 100;
+
+        public Ball getRandomBall() {
+            return new Ball(colorSupplier.getRandomColor(), random.nextInt(MAX_NUMBER + 1));
+        }
+    }


As mentioned in the previous review, the Color enum, and the ColorSupplier, Ball, and inner Lottery classes should each be in their own separate .java file. It's a standard Java convention to have one top-level public type per file. This nested structure makes the code hard to read and maintain. This also relates to checklist item #3 ('Don't use static methods'), as moving these classes to their own files will mean they no longer need to be static.

mateacademy-ai-mentor · 2026-02-26T16:17:26Z

Lottery.java

+        }
+    }
+
+    public static class Lottery {


This nested class has the same name as its outer class (Lottery), which is a major source of confusion. The logic and fields from this class (lines 34-40) should be part of the main public class Lottery defined on line 3. After moving the logic, this nested class should be removed.

whereisalemon-lab added 3 commits February 7, 2026 17:33

Initial commit

b5b93fe

lottery

442b7d2

add

3243152

mateacademy-ai-mentor suggested changes Feb 26, 2026

View reviewed changes

Update Lottery.java

b65ac46

whereisalemon-lab requested a review from mateacademy-ai-mentor February 26, 2026 16:00

mateacademy-ai-mentor suggested changes Feb 26, 2026

View reviewed changes

whereisalemon-lab added 2 commits February 26, 2026 17:04

Lottery.java

eda3252

Lottery.java

cb514e6

whereisalemon-lab requested a review from mateacademy-ai-mentor February 26, 2026 16:15

mateacademy-ai-mentor approved these changes Feb 26, 2026

View reviewed changes


		System.out.println("Drawing 3 balls");

		for (int i = 1; i <= 3; i++) {

		@@ -0,0 +1,54 @@
		import java.util.Random;

		public class LotterySystem {

Conversation

whereisalemon-lab commented Feb 26, 2026

Uh oh!

mateacademy-ai-mentor left a comment

Choose a reason for hiding this comment

Review Summary

Footnotes

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

mateacademy-ai-mentor left a comment

Choose a reason for hiding this comment

Review Summary

Footnotes

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

mateacademy-ai-mentor left a comment

Choose a reason for hiding this comment

Review Summary

Footnotes

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants