Book Image

Apache Spark 2.x for Java Developers

By : Sourav Gulati, Sumit Kumar
Book Image

Apache Spark 2.x for Java Developers

By: Sourav Gulati, Sumit Kumar

Overview of this book

Apache Spark is the buzzword in the big data industry right now, especially with the increasing need for real-time streaming and data processing. While Spark is built on Scala, the Spark Java API exposes all the Spark features available in the Scala version for Java developers. This book will show you how you can implement various functionalities of the Apache Spark framework in Java, without stepping out of your comfort zone. The book starts with an introduction to the Apache Spark 2.x ecosystem, followed by explaining how to install and configure Spark, and refreshes the Java concepts that will be useful to you when consuming Apache Spark's APIs. You will explore RDD and its associated common Action and Transformation Java APIs, set up a production-like clustered environment, and work with Spark SQL. Moving on, you will perform near-real-time processing with Spark streaming, Machine Learning analytics with Spark MLlib, and graph processing with GraphX, all using various Java packages. By the end of the book, you will have a solid foundation in implementing components in the Spark framework in Java to build fast, real-time applications.
Table of Contents (19 chapters)
Title Page
Credits
Foreword
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Interfaces


Interfaces are the reference types in Java. They are used in Java to define contracts among classes. Any class that implements that interface has to adhere to the contract that the interface defines.

For example, we have an interface car as follows that consists of three abstract methods:

public interface Car { 
   void shape(); 
   void price(); 
   void color(); 
} 

Any class that implements this interface has to implement all the abstract methods of this interface unless it is an abstract class. Interfaces can only be implemented or extended by other interfaces, they cannot be instantiated.

Prior to Java 8, interfaces consisted only of abstract methods and final variables. In Java 8, interfaces may contain default and static methods as well.

Static method in an interface

The static method in an interface is similar to the static method in a class. Users cannot override them. So even if a class implements an interface, it cannot override a static method of an interface.

Like a static...