Book Image

Mastering Concurrency Programming with Java 9 - Second Edition

By : Javier Fernández González
Book Image

Mastering Concurrency Programming with Java 9 - Second Edition

By: Javier Fernández González

Overview of this book

Concurrency programming allows several large tasks to be divided into smaller sub-tasks, which are further processed as individual tasks that run in parallel. Java 9 includes a comprehensive API with lots of ready-to-use components for easily implementing powerful concurrency applications, but with high flexibility so you can adapt these components to your needs. The book starts with a full description of the design principles of concurrent applications and explains how to parallelize a sequential algorithm. You will then be introduced to Threads and Runnables, which are an integral part of Java 9's concurrency API. You will see how to use all the components of the Java concurrency API, from the basics to the most advanced techniques, and will implement them in powerful real-world concurrency applications. The book ends with a detailed description of the tools and techniques you can use to test a concurrent Java application, along with a brief insight into other concurrency mechanisms in JVM.
Table of Contents (21 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback

Using streams to collect data

In Chapter 8, Processing Massive Datasets with Parallel Streams - The Map and Reduce Model, we made an introduction to streams. Let's remember their most important characteristics:

  • Streams don't store their elements. They only process the elements stored on a data source (a data structure, a file, and so on)
  • Streams can't be reusable
  • Streams make a lazy processing of data
  • The stream operation cannot modify the stream source
  • Streams allow you to chain operations so the output of one operation is the input of the next one

A stream is formed by the following three main elements:

  • A source that generates stream elements
  • Zero or more intermediate operations that generate output as another stream
  • One terminal operation that generates a result that could be either a simple object, array, collection, map, or anything else

The Stream API provides different terminal operations, but there are two more significant operations for their flexibility and power. In Chapter 8, Processing...