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http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
You want the ``Java “Java SE Development Kit 8u60'' 8u60” for whatever your computer happens to be. Oracle supports you for Windows, Mac OS X, and Linux.
If you're using an ``old'' “old” version of Java8 that you may have installed in prior months or years, this is a good time to update to the latest and greatest. Prof. Wallach started out writing code for Comp 215 with last year's ``8u25'' “8u25” version and managed to get the Java compiler to blow up on his perfectly reasonable and beautiful code. (That said, something that worked great for Prof. Wallach with 8u51 totally failed in the latest 8u60. We'll work through these issues when they occur. Don't panic.)
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Visit the IntellJ IDEA download site: https://www.jetbrains.com/idea/download/
and download the free ``community edition''free “community edition”. (There's nothing in the ``ultimate'' “ultimate” edition that will make any difference to your work in Comp215, Comp322, Comp311, or (hopefully) most other undergraduate computer science courses.) Versions are available for Windows, Mac OS X, and Linux. IntelliJ is an example of an integrated development environment (IDE). The other popular Java IDE you may have heard of or used in the past is Eclipse.
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If you've got something old around, this is a menu entry, File → New → Project... Otherwise, if you're staring at the ``Welcome “Welcome to IntelliJ IDEA'' ” tiny screen, there's a ``Create New Project'' a “Create New Project” button. Click it. Either way, you'll see many different kinds of projects to choose from. In the left column, near the bottom, it should offer you a ``Scala'' “Scala” project as an option. Select that. It will give you sub-options for "Scala", "SBT", and "Activator". Click "ScalaSBT". Then click "Next".
Locating Scala SDK and the JDK
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