Book Image

Java 9 with JShell

By : Gaston C. Hillar
Book Image

Java 9 with JShell

By: Gaston C. Hillar

Overview of this book

The release of Java 9 has brought many subtle and not-so-subtle changes to the way in which Java programmers approach their code. The most important ones are definitely the availability of a REPL, known as JShell, which will make experiments and prototyping much more straightforward than the old IDE-based project-led approach. Another, more subtle change can be seen in the module system, which will lead to more modularized, maintainable code. The techniques to take full advantage of object-oriented code, functional programming and the new modularity features in Java 9 form the main subjects of this book. Each chapter will add to the full picture of Java 9 programming starting out with classes and instances and ending with generics and modularity in Java.
Table of Contents (23 chapters)
Java 9 with JShell
Credits
About the Author
Acknowledgement
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Working with different collectors


We can follow a functional approach and solve different kinds of algorithms with stream processing pipelines and the help of the diverse collectors provided by Java 9, that is, the diverse static methods provided by the java.util.stream.Collectors class. In the next examples, we will use different arguments for the collect method.

The following lines join all the names for the MobileGame instances to generate a single String with the names separated with a separator ("; "). The code file for the sample is included in the java_9_oop_chapter_12_01 folder, in the example12_21.java file.

repository.getAll().stream()
.map(game -> game.name.toUpperCase())
.collect(Collectors.joining("; "));

The code passes Collectors.joining(";" ) as an argument to the collect method. The joining static method returns a Collector that concatenates the input elements into a String separated by the delimiter received as an argument. The following shows the results of executing the...