Installing the Java SDK

We are going to install the Oracle JDK, which includes a JVM and a Java compiler. On many Linux distributions, the open source OpenJDK is preinstalled. OpenJDK is fully compatible with the Oracle JDK, so if you already have it you do not need to install anything else to follow this book.

You might already have a Java SDK installed on your computer. We are going to check if this is the case. If you are using Windows, open a DOS Command Prompt. If you are using macOS or Linux, open a Terminal. After the prompt, type the following:

javac -version

If you have a JDK installed, the version of the installed compiler will be printed:

javac 1.8.0_112

If the version installed is greater than or equal to 1.8.0_112, you can skip the JDK installation. The version of Scala that we are going to use is compatible with JDK version 1.8 or 1.9.

If not, open the following URL, download the SDK for your platform, and follow the installation instructions given: http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html.