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Running the Simple KOTLIN program in IntelliJ

Lab Steps to Set Up IntelliJ and Write a Simple Hello World Program

** Setting up and configuring your IntelliJ Environment

Step 1: Download and Install IntelliJ IDEA

Visit IntelliJ IDEA Website:
Open your web browser and navigate to the
IntelliJ IDEA download page
⁠
.
Select Version:
Choose the appropriate version for your operating system (Windows, macOS, or Linux).
Download the Community Edition, which is free and sufficient for Kotlin development.
Install IntelliJ IDEA:
Windows:
Run the downloaded .exe file.
Follow the on-screen instructions to complete the installation.
macOS:
Open the downloaded .dmg file.
Drag and drop IntelliJ IDEA into the Applications folder.
Linux:
Extract the downloaded .tar.gz file.
Open a terminal and navigate to the extracted directory.
Run ./bin/idea.sh to start IntelliJ IDEA.

Step 2: Set Up IntelliJ IDEA for Kotlin Development

Launch IntelliJ IDEA:
Open IntelliJ IDEA from your installed applications.
Initial Configuration:
If this is your first time launching IntelliJ IDEA, you will be prompted to import settings. Choose "Do not import settings" if you don't have any previous configuration.
Follow the setup wizard to configure IntelliJ IDEA to your preferences.
done: Install Kotlin Plugin:
IntelliJ IDEA comes with Kotlin support out of the box. However, if prompted, ensure the Kotlin plugin is installed:
Go to File > Settings (or IntelliJ IDEA > Preferences on macOS).
Navigate to Plugins > Marketplace.
Search for "Kotlin" and click Install if it's not already installed.
Restart IntelliJ IDEA if prompted.

Step 3: Create a New Kotlin Project

Start a New Project:
On the Welcome screen, click New Project.
In the New Project window, select Kotlin on the left side.
Choose JVM | IDEA as the project type.
Click Next.
Project Configuration:
Set the project name to HelloWorld.
Choose the project location where you want to save your project.
Ensure the Project SDK is set (use the default JDK that comes with IntelliJ or specify a custom JDK if necessary).
Click Finish.

Step 4: Write a Simple Hello World Program

Create a Kotlin File:
In the Project view on the left, right-click the src folder.
Select New > Kotlin File/Class.
Name the file Main and choose File from the options.
Click OK.
Write the Hello World Program:
Open the Main.kt file if it's not already open.
Enter the following Kotlin code:
fun main() {
println("Hello, World!")
}

Step 5: Run the Hello World Program

Run the Program:
Right-click inside the Main.kt file and select Run 'MainKt'.
Alternatively, click the green run icon next to the main function.
View Output:
The Run window at the bottom of IntelliJ IDEA will open.
You should see the output Hello, World! printed in the console.

Step 6: Troubleshooting and Tips

Troubleshooting:
If you encounter any issues with the Kotlin plugin or SDK setup, revisit the plugin installation steps and ensure the correct JDK is selected.
For issues with running the program, check for typos in the code and ensure the main function is correctly defined.
Additional Tips:
Familiarize yourself with IntelliJ IDEA's shortcuts and features, such as code completion, refactoring tools, and debugging.
Explore the IntelliJ IDEA documentation and Kotlin language documentation for more advanced features and practices.
This completes the basic setup and first program execution in IntelliJ IDEA for Kotlin development.


When I do Right-click inside the Main.kt file - I do not see the option to Run 'MainKt'.


If the option to Run 'MainKt' is not appearing, it could be due to a few common issues such as incorrect project configuration or IntelliJ IDEA not recognizing the Kotlin runtime. Below are detailed steps to troubleshoot and resolve this issue:

Troubleshooting Steps to Enable Running Kotlin Programs

Step 1: Verify Kotlin Plugin Installation

Check Kotlin Plugin:
Go to File > Settings (or IntelliJ IDEA > Preferences on macOS).
Navigate to Plugins > Installed.
Ensure the Kotlin plugin is listed and enabled. If not, go to the Marketplace tab, search for "Kotlin," and install it.

Step 2: Verify Project SDK and Kotlin Configuration

Check Project SDK:
Go to File > Project Structure.
Ensure the Project SDK is set correctly. If it's not, click New, select the appropriate JDK, and apply the changes.
Check Kotlin Configuration:
Right-click the src folder in the Project view.
Select New > Kotlin File/Class and ensure the file type is set to File.
If there is an option to configure the Kotlin runtime in the src folder, follow the prompts to do so.

Step 3: Ensure Correct Main Function Definition

Verify Main Function:
Ensure your Main.kt file contains a properly defined main function:
kotlin
Copy code
fun main() { println("Hello, World!") }

Step 4: Invalidate Caches and Restart

Invalidate Caches:
Go to File > Invalidate Caches / Restart.
Click Invalidate and Restart to refresh the IntelliJ IDEA caches. This can resolve many issues related to project configuration.

Step 5: Run Configuration

Create a Run Configuration Manually:
Go to Run > Edit Configurations.
Click the + icon to add a new configuration.
Select Kotlin from the list (if not available, select Application and manually configure it for Kotlin).
Name the configuration MainKt.
Set the Main class to MainKt (or your file name without the .kt extension).
Apply and close the configuration dialog.
Run the Program:
With the new configuration set, try running it again:
Select Run > Run... and choose MainKt.
Alternatively, use the run icon next to the configuration name at the top-right of the IntelliJ IDEA window.

Detailed Steps from Start to Finish

To ensure all steps are covered comprehensively, follow the complete process from setting up the project to running the program:
Create a New Kotlin Project:
Open IntelliJ IDEA.
On the Welcome screen, click New Project.
Select Kotlin on the left, choose JVM | IDEA, and click Next.
Set the project name to HelloWorld, choose the project location, ensure the Project SDK is set, and click Finish.
Create a Kotlin File:
In the Project view, right-click the src folder.
Select New > Kotlin File/Class.
Name the file Main and choose File.
Click OK.
Write the Hello World Program:
Open the Main.kt file if not already open.
Enter the following code:
kotlin
Copy code
fun main() { println("Hello, World!") }
Ensure the Kotlin Plugin and SDK Are Correct:
Check that the Kotlin plugin is installed and enabled.
Verify the Project SDK and ensure it's correctly configured for Kotlin.
Run the Program:
Right-click inside the Main.kt file.
If Run 'MainKt' is not available, create a new Run Configuration manually as described above.
Invalidate Caches and Restart if Necessary:
If issues persist, invalidate caches and restart IntelliJ IDEA.
By following these detailed steps, you should be able to run your Kotlin program successfully in IntelliJ IDEA. If problems persist, consider checking the IntelliJ IDEA and Kotlin documentation or seeking support from relevant developer communities.
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