Bael 1166 intro apache spark (#2812)

* Changes for BAEL-1166

* Changes for BAEL_1166

* Changes for BAEL 1166

* Changes for BAEL 1166

apache-spark/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+	<groupId>com.baeldung</groupId>
+	<artifactId>apache-spark</artifactId>
+	<version>1.0-SNAPSHOT</version>
+	<packaging>jar</packaging>
+
+	<name>apache-spark</name>
+	<url>http://maven.apache.org</url>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+	</properties>
+
+	<dependencies>
+		<!-- https://mvnrepository.com/artifact/org.apache.spark/spark-core_2.10 -->
+		<dependency>
+			<groupId>org.apache.spark</groupId>
+			<artifactId>spark-core_2.10</artifactId>
+			<version>2.2.0</version>
+		</dependency>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>3.8.1</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.7.0</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+</project>

apache-spark/src/main/java/com/baeldung/WordCount.java

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+package com.baeldung;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.regex.Pattern;
+
+import org.apache.spark.SparkConf;
+import org.apache.spark.api.java.JavaPairRDD;
+import org.apache.spark.api.java.JavaRDD;
+import org.apache.spark.api.java.JavaSparkContext;
+import org.apache.spark.api.java.function.*;
+import org.apache.spark.api.java.function.Function2;
+import org.apache.spark.api.java.function.PairFunction;
+
+import scala.Tuple2;
+
+public class WordCount {
+
+    private static final Pattern SPACE = Pattern.compile(" ");
+    
+    public static void main(String[] args) throws Exception {
+    if (args.length < 1) {
+        System.err.println("Usage: JavaWordCount <file>");
+        System.exit(1);
+    }
+    SparkConf sparkConf = new SparkConf().setAppName("JavaWordCount").setMaster("local");
+    JavaSparkContext ctx = new JavaSparkContext(sparkConf);
+    JavaRDD<String> lines = ctx.textFile(args[0], 1);
+
+    JavaRDD<String> words = lines.flatMap(s -> Arrays.asList(SPACE.split(s)).iterator());
+    JavaPairRDD<String, Integer> ones = words.mapToPair(
+      new PairFunction<String, String, Integer>() {
+          @Override
+          public Tuple2<String, Integer> call(String s) {
+              return new Tuple2<>(s, 1);
+          }
+      });
+
+    JavaPairRDD<String, Integer> counts = ones.reduceByKey(
+      new Function2<Integer, Integer, Integer>() {
+          @Override
+          public Integer call(Integer i1, Integer i2) {
+              return i1 + i2;
+          }
+      });
+
+    List<Tuple2<String, Integer>> output = counts.collect();
+    for (Tuple2<?, ?> tuple : output) {
+        System.out.println(tuple._1() + ": " + tuple._2());
+    }
+    ctx.stop();
+}
+}

apache-spark/src/main/resources/spark_example.txt

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+Hello from Baeldung
+Keep Learning Spark
+Bye from Baeldung