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

Test your knowledge


  1. A default method allows us to declare:

    1. A default constructor for an interface that Java will use when the class that implements the interface doesn't declare a constructor.

    2. A method that will be called before any method is executed for the instance of a class that implements the interface.

    3. A default implementation for a method in an interface that Java will use when a class that implements the interface doesn't provide its own implementation of this method.

  2. Consider that we have an existing interface that many classes implement and all the classes compile without errors. If we add a default method to this interface:

    1. The classes that implement the interface won't compile until they provide an implementation for the new method requirement.

    2. The classes that implement the interface won't compile until they provide an implementation for the new constructor requirement.

    3. The classes that implement the interface will compile.

  3. Which of the following keywords allow us to determine whether...