To get the most out of this book, you should have a decent level of Java programming knowledge. It is assumed that you know the basics of Java threading. Here I cover the essential aspects as a refresher. Having worked through some Java threading examples would be definite plus. You should also be comfortable using maven, the Java build tool.
Using an IDE of your choice IntelliJ Idea, Eclipse or Netbeans would be helpful - but is not strictly necessary. To illustrate the functional concurrency patterns - the last two chapters use Scala. The code uses basic Scala constructs. It would be good to go through an introductory Scala tutorial - and you should be good to go.