2. Software Prerequisites

We will be using Scala (Version 2) as a main programming language for this course.

The setup outlined below has been tested on Windows 11 and macOS (for both Intel and Apple silicon chips). If you experience issues at any stage of the setup, please refer to the Troubleshooting section below.

2.1. Getting Scala and IntelliJ

In your preparation for the first lecture, please install the following software artefacts (or make sure that you have them installed in your system):

Java SDK 11. You will need to make an Oracle account to download the latest version.
Scala Build Tool (sbt)
IntelliJ IDEA Community Edition. When you start IntelliJ for the first time, make sure to choose Scala plugin when IntelliJ IDEA suggests you to download featured plugins.
Scala plugin for IntelliJ IDEA (if not installed in the previous step)

This setup has been last checked with sbt version 1.6.2 and IntelliJ IDEA 2023.1.4.

2.2. Working with Multiple Java Versions

If you want to maintain multiple versions of Java Development Kit on your machine, consider installing the utility tool jenv (available for download here). Follow the instructions on the linked webpage to switch between multiple versions and add already installed versions to jenv list.

2.3. Working with Version Control

The code from the lectures will be disseminated via GitHub using the git version control system. If you don’t have a GitHub account yet, please, create one for yourself. git comes installed on most of Unix systems. It can be downloaded for Windows via this link.

Make sure that you are comfortable with the git operations, such as clone, pull, add, commit, and push. Some resources that might be helpful:

2.4. Checking your Setup

The code appearing in the lectures will be collected in this repository with examples. In order to be able to access it, please, make sure to email your GitHub name to the instructor—this is necessary to grant you GitHub access for course-related repositories.

To check your Scala setup, clone this project from GitHub (via git@github.com:ysc4231/lectures-2022.git). Next, try to execute the following two commands in the terminal from the root of your project (it will take a few minutes the first time you run it, as sbt needs to download all the dependencies):

sbt test

will run the tests in the project. You may also run:

sbt

and then, from the sbt console:

runMain basic.HelloWorld

This will execute a simple script printing (after dumping some rather verbose log information about software updates and compilation) the message Hello, World! to the output.

You can now exit sbt console by typing:

exit

Finally, you can try to open this project in IntelliJ IDEA via “File -> Open” and choosing the project folder. Click “OK” when asked about initial project settings.

2.5. Troubleshooting

Problem: I am trying to open the project in IntelliJ IDEA for the first time, and, while importing it via sbt, it fails with an error:
```
Extracting structure failed: Build status: Error
sbt task failed, see log for details
```
This problem has been detected on macOS.

Solution: Close the project (via File -> Close Project), then follow the instructions here to import the project using BSP instead of SBT. The instructions there are given for macOS; on Windows, the first action dialogue shortcut is Ctrl+Shift+A.
Problem: Opening the project for the first time in IntelliJ fails with a pop-up notification:
```
sbt import cancelled: Cannot run program
```
This problem has been observed on Windows 11.

Solution Open File -> Project Structure, category Project Settings -> Project and select a Java SDK (e.g. OpenJDK version 11.0.5 or similar one) from what’s already installed at your system.