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. In Java 9, a subclass:

    1. Inherits all the constructors from its superclass.

    2. Doesn't inherit any constructor from its superclass.

    3. Inherits the constructor with the largest number of arguments from its superclass.

  2. We can declare abstract methods:

    1. In any class.

    2. Only in an abstract class.

    3. Only in a concrete subclass of an abstract class.

  3. A concrete subclass of any abstract class:

    1. Must provide an implementation for all the inherited abstract methods.

    2. Must provide an implementation for all the inherited constructors.

    3. Must provide an implementation for all the inherited abstract fields.

  4. Which of the following lines declare an abstract class named Dog as a subclass of VirtualAnimal:

    1. public abstract class Dog subclasses VirtualAnimal

    2. public abstract Dog subclasses VirtualAnimal

    3. public abstract class Dog extends VirtualAnimal

  5. Which of the following annotations indicated before a method's declaration informs the Java 9 compiler that the method is meant to override the method with the same name...