Concurrency In Scala

Matthew Rathbone shows different concurrency options available in Scala:

Scala is a functional programming language that aims to avoid side effects by encouraging you to use immutable variables (called ‘values’), and data structures.

So by default in Scala when you build a list, array, string, or other object, that object is immutable and cannot be changed or updated.

This might seem unrelated, but think about a thread which has been given a list of strings to process, perhaps each string is a website that needs crawling.

In the Java model, this list might be updated by other threads at the same time (adding / removing websites), so you need to make sure you either have a thread-safe list, or you safeguard access to it with the protected keyword or a Mutex.

By default in Scala this list is immutable, so you can be sure that the list cannot be modified by other threads, because it cannot be modified at all.

While this does force you to program in different ways to work around the immutability, it does have the tremendous effect of simplifying thread-safety concerns. The value of this cannot be understated, it’s a huge burden to worry about thread safety all the time, but in Scala much of that burden goes away.

Read the whole thing if you’re looking at writing Spark applications in Scala.  If you’re thinking about functional programming in .NET languages, F# is  there for you.

Related Posts

Static Site Generation With Hugo

Steph Locke explains how to build a simple site using Hugo: This site uses Hugo. Hugo is a “static site generator” which means you write a bunch of markdown and it generates html. This is great for building simple sites like company leafletware or blogs. You can get Hugo across platforms and on Windows it’s […]

Read More

Using Azure Cloud Shell

Jeffrey Verheul shows off a bit of Azure Cloud Shell: Connecting to a database Now that your Cloud Shell is ready to go, you can start using Bash. This means you can also use sqlcmd from within Bash. You can connect to a database with sqlcmd, by using the following command: sqlcmd -S -U […]

Read More


March 2017
« Feb Apr »