Scastie

Scastie (https://scastie.scala-lang.org) is a great online resource for trying out small Scala code snippets. All that is needed is a web browser and access to the internet.

The main screen is divided into two parts: the top part consists of a program and its output and the bottom part is the output from the backend server that compiles and runs the code. You can modify the code and run it any number of times by using the Run option, as shown in the following screenshot:

When run in the browser, this simple example displays what is going on in each step. In our example, the Scala expression produced Hello, World!, which is of the java.lang.String type. The expression is of the following pattern:

List of strings joined together by a comma with an exclamation mark suffix.