Book Image

Java 9: Building Robust Modular Applications

By : Dr. Edward Lavieri, Peter Verhas, Jason Lee
Book Image

Java 9: Building Robust Modular Applications

By: Dr. Edward Lavieri, Peter Verhas, Jason Lee

Overview of this book

Java 9 and its new features add to the richness of the language; Java is one of the languages most used by developers to build robust software applications. Java 9 comes with a special emphasis on modularity with its integration with Jigsaw. This course is your one-stop guide to mastering the language. You'll be provided with an overview and explanation of the new features introduced in Java 9 and the importance of the new APIs and enhancements. Some new features of Java 9 are ground-breaking; if you are an experienced programmer, you will be able to make your enterprise applications leaner by learning these new features. You'll be provided with practical guidance in applying your newly acquired knowledge of Java 9 and further information on future developments of the Java platform. This course will improve your productivity, making your applications faster. Next, you'll go on to implement everything you've learned by building 10 cool projects. You will learn to build an email filter that separates spam messages from all your inboxes, a social media aggregator app that will help you efficiently track various feeds, and a microservice for a client/server note application, to name just a few. By the end of this course, you will be well acquainted with Java 9 features and able to build your own applications and projects. This Learning Path contains the best content from the following two recently published Packt products: • Mastering Java 9 • Java 9 Programming Blueprints
Table of Contents (33 chapters)
Title Page - Courses
Packt Upsell - Courses
Taking Notes with Monumentum

Waiting for processes

When a process starts another process, it may wait for the process many times because it needs the result of the other program. If the structure of the task can be organized in a way that the parent program can do something else while waiting for the child process to finish, then the parent process can invoke the isAlive() method on the process handle. Many times, the parent process has nothing to do until the spawned process finishes. Old applications implemented loops that called the Thread.sleep() method so CPU was not excessively wasted and from time to time the process was checked to see if it was still alive. Java 9 offers a much better approach to the waiting process.

The ProcessHandle interface has a method called onExit that returns a CompletableFuture. This class was introduced in Java 8 and makes it possible to wait for a task to be finished without looping. If we have the handle to a process we can simply call the handle.onExit().join() method to wait until...