Assignment 0 – Setup and Working Environment

OOP 2026 · Ariel University

Goal:
The goal of this setup assignment is to ensure that you have a complete and working Java environment for the OOP course.

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1. IntelliJ IDEA Setup

We will use IntelliJ IDEA Community Edition as our development environment.

• Download and install IntelliJ IDEA Community Edition from
  https://www.jetbrains.com/idea/download
• During installation, make sure to:
  • Select Add “bin” folder to PATH (optional but useful)
  • Associate .java files with IntelliJ IDEA

Your computer must have JDK 21 or higher installed and configured in IntelliJ.
When creating a project, verify that IntelliJ detects and uses Java 21+.

How to check inside IntelliJ

1. When creating the project:

   • In the New Project window, look for the field “JDK”.
   • If it shows something like jdk-21 or openjdk-21, you’re good.
   • If not, click “Add SDK → Download JDK” or “Add JDK” and select the folder where your JDK 21 is installed (e.g.,
     C:\Program Files\Java\jdk-21).

2. After the project is created:

   • Open the top menu: File → Project Structure → Project
   • Under Project SDK, it should say 21 (or higher).
   • Under Project language level, choose “21 – (Switch expressions, string templates, etc.)”
     (If you’re not sure, pick the highest available level.)

3. Optional quick check:

   • In IntelliJ’s Terminal (bottom panel), type:

     java -version
     

     You should see:

     openjdk version "21.0.x"
     

     confirming your environment is using JDK 21.

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2. Create and Run Your First Java Project

1. Open IntelliJ IDEA → click “New Project”
2. Select Java, and make sure the JDK is version 21 or newer.
3. Name your project Assignment0_HelloWorld.
4. IntelliJ will create a structure like:

   Assignment0_HelloWorld/
     .idea/
     src/
     Assignment0_HelloWorld.iml
   

5. In the src/ folder, create a new Java file named HelloWorld.java:

/**
 * @author YourName
 */
public class HelloWorld {
    /**
     * A simple demo program to verify your setup.
     *
     * @param args command line arguments
     */
    public static void main(String[] args) {
        for (int i = 0; i < 5; i++) {
            System.out.println("Hi");
        }
    }
}

6. Click the green ▶ icon next to the main method or at the top of the editor to run the program.
   The output should be:

   Hi
   Hi
   Hi
   Hi
   Hi
   

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3. Understanding IntelliJ’s Build System

When you create a project, IntelliJ automatically manages your build and configuration files.
Here’s a short explanation of what’s going on behind the scenes:

• .idea/ folder – contains project-specific settings and configuration files.
• modules.xml – defines the modules in your project (e.g., source roots, output paths).
• workspace.xml – stores personal preferences such as window layout and run configurations.
• misc.xml – holds general project settings (e.g., JDK version, compiler options).
• .iml file – defines each module’s source folders and dependencies.

You should not edit these files manually — IntelliJ manages them automatically.
They make sure IntelliJ knows how to build, compile, and run your project correctly.

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4. Submission Checklist

✅ IntelliJ IDEA installed and working
✅ JDK 21 or higher configured
✅ “HelloWorld.java” runs successfully

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Once all items above are verified, you’re ready to start the real assignments!