Installation instructions on a Mac

Step 0: Adjust your keyboard language

While using the software for this course, your computer’s keyboard language must be set to English. If needed, please follow these instructions to change your keyboard language.

Step 1: Install VSCodium

Preliminary notes

We recommend VSCodium as the IDE (integrated development environment) for this course. It is based on an IDE called VS Code that is commonly used by professional programmers, but VSCodium has generative AI features turned off by default and no pre-installed extensions. The use of AI tools is not permitted in this course, and using VSCodium will make it easier for you to become proficient in writing code on your own.
You are welcome to use a different IDE for Java if you prefer. However, even students who have already used another IDE find it convenient to install VSCodium specifically for their work in this course. Note that it is possible to install VSCodium alongside an existing VS Code installation, since VSCodium has its own, separate configuration file from VS Code.

Before downloading VSCodium, determine whether your Mac uses Apple silicon or an Intel processor. You can also consult Apple’s list of Mac computers with Apple silicon:

Select the Apple menu in the upper-left corner of the screen.
Select About This Mac.
On a Mac with Apple silicon, About This Mac shows an item labeled Chip, followed by the name of the chip (for example, Apple M1).
On an Intel-based Mac, About This Mac shows an item labeled Processor, followed by the name of an Intel processor (for example, Intel Core i5).

Then install VSCodium:

Go to the VSCodium releases page.
Scroll down to the table of download links for the latest release, and download the appropriate .dmg file:
- Apple Silicon Macs: choose the file whose name begins with VSCodium.arm64 and ends with .dmg.
- Intel Macs: choose the file whose name begins with VSCodium.x64 and ends with .dmg.
Go to your Downloads folder and double-click the .dmg file that you downloaded.
Drag the VSCodium icon into the Applications folder.
Launch VSCodium.

First-time confirmation

The first time that you open VSCodium, macOS may warn you that the application was downloaded from the Internet. Click Open to confirm you want to open it.

Step 2: Install a JDK

Java programs are compiled and run using a tool called the Java Development Kit, or JDK. For this course, please install a recent version (25 or newer).

After a JDK is installed, the javac and java commands become available.

On macOS, install OpenJDK using SDKMAN. SDKMAN installs Java in your home folder and updates your shell so that commands like java and javac use the installed JDK.

Launch VSCodium.
Open VSCodium’s built-in Terminal pane. You can do this by pressing the Control key and the backtick key, or by selecting Terminal->New Terminal from the menu.
In the Terminal, install SDKMAN by typing the following command and pressing Enter:
```
curl -s "https://get.sdkman.io" | zsh
```
Follow the on-screen instructions.
When the SDKMAN installer is finished, close the current Terminal pane and open a fresh Terminal pane in VSCodium.
In the new Terminal pane, confirm that SDKMAN is working by typing the following command and pressing Enter:
```
sdk version
```
Install OpenJDK by typing the following command and pressing Enter:
```
sdk install java
```
SDKMAN installs the latest stable Java release using Eclipse Temurin by default. If SDKMAN asks whether this version should be set as the default, press Enter.

Step 3: Verify the JDK installation

If VSCodium is not already open, launch it.
Open VSCodium’s built-in Terminal pane. You can do this by pressing the Control key and the backtick key, or by selecting Terminal->New Terminal from the menu.
In the Terminal, type the following command and then press Enter:
```
java -version
```
You should see output that looks similar to this:
```
> java -version
openjdk version "25.0.1" 2025-10-21 LTS
OpenJDK Runtime Environment Temurin-25.0.1+8 (build 25.0.1+8-LTS)
OpenJDK 64-Bit Server VM Temurin-25.0.1+8 (build 25.0.1+8-LTS, mixed mode, sharing)
```
The exact version may be different, but the output should include “Temurin” and a recent Java version number.