Begenner at spark Big data programming (spark code) - hadoop

Question

i'm learning spark for distributed systemes. i runned this code and it's worked.
but i know that it's count word in input files but i have probleme undestanding how Methods are written and what the us of JavaRDD
public class JavaWordCount {
public static void main(String[] args) throws Exception {
System.out.print("le programme commence");
//String inputFile = "/mapr/demo.mapr.com/TestMapr/Input/alice.txt";
String inputFile = args[0];
String outputFile = args[1];
// Create a Java Spark Context.
System.out.print("le programme cree un java spark contect");
SparkConf conf = new SparkConf().setAppName("JavaWordCount");
JavaSparkContext sc = new JavaSparkContext(conf);
// Load our input data.
System.out.print("Context créeS");
JavaRDD<String> input = sc.textFile(inputFile);
// map/split each line to multiple words
System.out.print("le programme divise le document en multiple line");
JavaRDD<String> words = input.flatMap(
new FlatMapFunction<String, String>() {
#Override
public Iterable<String> call(String x) {
return Arrays.asList(x.split(" "));
}
}
);
System.out.print("Turn the words into (word, 1) pairse");
// Turn the words into (word, 1) pairs
JavaPairRDD<String, Integer> wordOnePairs = words.mapToPair(
new PairFunction<String, String, Integer>() {
#Override
public Tuple2<String, Integer> call(String x) {
return new Tuple2(x, 1);
}
}
);
System.out.print(" // reduce add the pairs by key to produce counts");
// reduce add the pairs by key to produce counts
JavaPairRDD<String, Integer> counts = wordOnePairs.reduceByKey(
new Function2<Integer, Integer, Integer>() {
#Override
public Integer call(Integer x, Integer y) {
return x + y;
}
}
);
System.out.print(" Save the word count back out to a text file, causing evaluation.");
// Save the word count back out to a text file, causing evaluation.
counts.saveAsTextFile(outputFile);
System.out.println(counts.collect());
sc.close();
}
}

Answer 1

As mentioned by PinoSan this question is probably too generic, and you should be able to find your answer in any Spark Getting Started, or Tutorial.
Let me point you to some interesting content:
Spark Quick Start Guide
Getting Started with Apache Spark, ebook
Introduction to Apache Spark with Examples and Use Cases
Disclaimer: I am working for MapR this is why I put online resources on Spark from MapR site