2. Installing Scala

2.1. Prerequisite: JDK

As a prerequisite to Scala development, we recommend that you install the Oracle Java Development Kit (Java 7 SE 7u51 or later). While you can work with OpenJDK and other VM implementations to run Scala, our initial testing is that the best experience and performance comes from the latest stable release of the Java 7 Platform.

• Oracle Java Platform Downloads [http://www.oracle.com/technetwork/java/javase/downloads/]

2.2. Command-Line Tools

We do most of our CS1 instruction using command line tools. If you want to go this route, you can perform a standard Scala 2.10.x standalone install using your system’s package manager or manually from

• http://www.scala-lang.org/download/

This is generally a good choice for projects without external dependencies.

For projects with external dependencies (such as unit testing), we also recommend using sbt (Simple Build Tool for Scala). You can install version 0.13.x or newer of sbt using your system’s package manager or manually from

• http://www.scala-sbt.org/release/docs/Getting-Started/Setup.html

You may also need to configure the paths on your machine to make these tools easy to work with.

2.3. Text Editors

To go along with the command-line tools, you will need a text editor that you like to work with.

• On Linux, we recommend Vim [http://www.vim.org/] or Emacs [https://www.gnu.org/software/emacs/]. OS X Terminal also supports both via the command line or via the MacVim [https://code.google.com/p/macvim/] and AquaMacs [http://aquamacs.org/] projects.
• The Sublime Text Editor [http://www.vim.org] is also wildly popular among agile developers and works on all major platforms. While not free/open source, it can be used for an indefinite period for free (with only occasional nagging suggesting you upgrade to the paid version). George uses this editor not only for writing Scala but also for editing reStructuredText (the source code for these notes).

2.4. IDE Option: JetBrains IntelliJ IDEA

Many faculty teaching introductory CS courses prefer an Integrated Development Environment (IDE). We recommend IntelliJ IDEA, which is growing in popularity over Eclipse and preferred by many of us. You can get the Community edition for free from the following URL and then install the Scala plugin through the plugin manager.

• http://www.jetbrains.com/idea/download/

The IntelliJ IDEA Scala plugin undergoing active development, and there is a tradeoff between stability and features/bug fixes. For advanced Scala development, you may find yourself wanting to be more bleeding edge. To this end, we recommend the current early access version:

• http://confluence.jetbrains.com/display/IDEADEV/IDEA+13.1+EAP

When you install the Scala plugin through the plugin manager, you will automatically get the version that matches that of IDEA. There are still a few glitches, but it has gotten a lot better since January 2014. In particular, compilation (and execution of Scala worksheets) has become much faster.

To work around false compilation errors in Scala worksheets, we also recommend a standalone installation of Scala (sufficient for projects without external dependencies) or sbt.

2.5. IDE Option: Eclipse Scala IDE

The official Scala IDE is provided as an Eclipse bundle that has Scala already installed. It will work on all platforms with very minor differences. The following link will take you there.

• http://scala-ide.org/download/sdk.html