Working With Spark And Scala In IntelliJ Idea - Part One


In this article, we will see how to set up Scala in IntelliJ IDEA and we will create a Spark application using the Scala language and run it with our local data. I am using Indian Pincode data to analyze the state-by-state post office details.
Scala is a very powerful object-oriented and functional programming language. Scala's static types help avoid bugs in complex applications, and its JVM (Java Virtual Machine) lets you build high-performance systems with easy access to huge ecosystems of libraries.
Scala source code is intended to be compiled to Java bytecode so that the resulting executable code runs on a Java virtual machine (JVM).
Scala provides language interoperability with Java, so that libraries written in both languages may be referenced directly in Scala or Java.
Please refer to the official Scala documentation for more details.
As Scala runs in JVM, it needs a Java Runtime/Java Development Kit.
Step 1 - Install Java Development Kit (JDK version 8)
Please note that Scala’s latest version (2.11/2.12) is not fully compatible with higher versions of Java. We must choose the Java 8 version to avoid issues.
Please download JDK version 8 from this URL and install it to your windows machine.
Please accept the license agreement and install it. This will first install JDK to your system.
After installing the JDK it will install Java Runtime also (JRE)
Step 2 - Install IntelliJ IDEA with Scala and Azure Plugins
We have now successfully installed JDK and JRE in our system. Now we can install IntelliJ IDEA in our machine. This is a wonderful IDE suitable for Java and Scala development. It is a product of JetBrains company. Please download IntelliJ free community edition from this link
We can install the Scala plugin along with the IntelliJ installation. If you forgot to install it, please install this plugin separately.
Our installation will take some time to finish and after installation, we can open the IntelliJ IDEA.
We are going to work with Spark and Scala along with Azure HDInsight. We need an Azure plugin too. Please click “Configure” and choose “Plugins” from the dropdown list.
We can search for Azure and will find an Azure Toolkit for IntelliJ. Please install this plugin to your IntelliJ.
After successful plugin installation please re-run the IntelliJ.
Step 3 - Create a new Spark Scala Project
We can choose “Create New Project”
Please choose the “Azure Spark/HDInsight” and “Spark Project (Scala)” option and click the “Next” button. Select a build tool as “Maven”. Maven will help us to build and deploy our application.
Please choose a valid name for our project. Also select Project SDK (choose Java installation path from your local system) and select Spark version. Here I choose Spark 2.3.0 with the Scala 2.11.8 version. Now click the “Finish” button.
After some time, our project will be created successfully. Please look at the default project structure. The project contains an “artifacts” folder which will be used for creating project artifacts. Normally Java/Scala Jar files created in this artifacts folder. Another “data” folder will be used to save local data files. In this article, we will see how to read one CSV file from this data folder.
“src” folder will contain all the source code files. We can combine both Java and Scala in the same project easily.
The project also contains a “pom.xml” file. This is the main file of all the Maven projects. This file will contain all the external dependencies information about our project. As we have created a Spark project this file contains the “spark-core” and “spark-SQL” libraries. Maven will automatically download these references from Maven global repository and save it to a local folder. In future projects, it will refer to local reference only.
For our first project, it takes some more time to install all the dependencies in our local system. After some time, our new project will be ready. Now we can create a new Scala Object under the “sample” package. Java is a package-based application. Scala also follows the same tradition.
Please give a valid name to our new Scala object. Please choose “Kind” as “Object”
I have downloaded the Pincode data from the Indian government official website for evaluation purposes and saved it to our default data folder. You must save data using this folder structure.
We can add the below source code to our “indianpincode” object file.
  1. package sample    
  2. import org.apache.spark.sql.SparkSession    
  3. object indianpincode {    
  4.     def main(arg: Array[String]): Unit = {    
  5.         val sparkSession: SparkSession = SparkSession.builder.master("local").appName("Scala Spark Example").getOrCreate()    
  6.         val csvPO ="inferSchema"true).option("header"true).    
  7.         csv("all_india_PO.csv")    
  8.         csvPO.createOrReplaceTempView("tabPO")    
  9.         val count = sparkSession.sql("select * from tabPO").count()    
  10.         print(count)    
  11.     }    
  12. }  
In this code, we have imported “org.apache.spark.sql.SparkSession” library. SparkSession will help us to create a spark session in the runtime and we can execute all Spark-related queries in our project easily.
In the next step, we have read the CSV file from our local mapped data folder and saved to a data frame variable “csvPO”
Next, we will create a temporary view from the above data frame variable.
We are using Spark SQL to query the data. Spark SQL is easy to use, and it looks like normal SQL queries.
We simply get the total record count of Pin code data and save it to a variable and we print that variable.
Step 4 - Run the Project
We can run our project now. Please click the Run menu and choose the “Edit Configurations” option.
We can add a newconfiguration now. Please choose the “Azure HDInsight Spark” type. 
Give a name to our configuration and select the main class to run. In our case, this is an object file.
Please note running Spark application in the windows machine needs a winutils.exe utility.
Please download this utility from this link and copy it to your local directory. Please set an environment variable for this utility.
Please right-click our object file “indianpincode.scala” and choose Run option. This will run our application locally.
It will take some moments to compile our application and we will get a result after some time. We have just taken the record count in this query.
Now we can add one more line of code to get the state-by-state post office count. Run the application again in the same way and we will get the below result now.
  1. sparkSession.sql("select statename as StateName,count(*) as TotalPOs from tabPO group by statename order by count(*) desc").show(50)   
In this article, we saw how to install IntelliJ IDEA in our windows machine and we also installed Scala and Azure plugins in IntelliJ. Later we created a simple Spark Scala project and read the data from the local CSV file.
In the second part of this article, we will run the same application with the HDInsight spark cluster. I will explain all the steps to create an HDInsight spark cluster in the Azure portal.

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