Book Image

Java 9 Concurrency Cookbook, Second Edition - Second Edition

By : Javier Fernández González
Book Image

Java 9 Concurrency Cookbook, Second Edition - Second Edition

By: Javier Fernández González

Overview of this book

Writing concurrent and parallel programming applications is an integral skill for any Java programmer. Java 9 comes with a host of fantastic features, including significant performance improvements and new APIs. This book will take you through all the new APIs, showing you how to build parallel and multi-threaded applications. The book covers all the elements of the Java Concurrency API, with essential recipes that will help you take advantage of the exciting new capabilities. You will learn how to use parallel and reactive streams to process massive data sets. Next, you will move on to create streams and use all their intermediate and terminal operations to process big collections of data in a parallel and functional way. Further, you’ll discover a whole range of recipes for almost everything, such as thread management, synchronization, executors, parallel and reactive streams, and many more. At the end of the book, you will learn how to obtain information about the status of some of the most useful components of the Java Concurrency API and how to test concurrent applications using different tools.
Table of Contents (12 chapters)

Separating the launching of tasks and the processing of their results in an executor

Normally, when you execute concurrent tasks using an executor, you will send Runnable or Callable tasks to the executor and get Future objects to control the method. You can find situations where you need to send the tasks to the executor in one object and process the results in another one. For such situations, the Java Concurrency API provides the CompletionService class.

The CompletionService class has a method to send tasks to an executor and a method to get the Future object for the next task that has finished its execution. Internally, it uses an Executor object to execute the tasks. This behavior has the advantage of sharing a CompletionService object and sending tasks to the executor so others can process the results. The limitation is that the second object can only get the Future objects for those tasks that have finished...