This article introduces Scala to those Java developers who don't know Scala. I assume here that you already know Java (preferably Java 8) so that you can compare the features of Scala with Java. Please be informed that this article is not an end to end Scala tutorial. I am covering only the fundamentals of Scala which are used in my Apache Spark tutorials.
First of all, remember that Scala is a JVM based language which is running on top of your regular Java Virtual Machine. The whole purpose of Scala is providing a convenient functional programming language (at that time Java 8 wasn't there). However since Scala is built on top of Java, you can access Java libraries and API from your Scala code.
To play with Scala, please setup Scala on IntelliJ IDEA or install a command line Scala version in your system.