ClassNotFoundException while running MissingPokerCards on ec2 Instance

Question

I'm getting the following error when I try to run jar file -

        Exception in thread "main" java.lang.ClassNotFoundException: finalPoker.MissingPokerCards
                at java.net.URLClassLoader$1.run(URLClassLoader.java:360)
                at java.net.URLClassLoader$1.run(URLClassLoader.java:349)
                at java.security.AccessController.doPrivileged(Native Method)
                at java.net.URLClassLoader.findClass(URLClassLoader.java:348)
                at java.lang.ClassLoader.loadClass(ClassLoader.java:430)
                at java.lang.ClassLoader.loadClass(ClassLoader.java:363)
                at java.lang.Class.forName0(Native Method)
                at java.lang.Class.forName(Class.java:278)
                at org.apache.hadoop.util.RunJar.main(RunJar.java:153)

The following code is my MissingPokerCards program which will count the number of missing cards from the deck of 52 cards.

    package MissingPokerCards;
    import java.io.IOException;
    import java.util.ArrayList;

    import org.apache.hadoop.conf.Configuration;
    import org.apache.hadoop.fs.Path;
    import org.apache.hadoop.io.IntWritable;
    import org.apache.hadoop.io.LongWritable;
    import org.apache.hadoop.io.Text;
    import org.apache.hadoop.mapreduce.Job;
    import org.apache.hadoop.mapreduce.Mapper;
    import org.apache.hadoop.mapreduce.Reducer;
    import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
    import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

    public class PokerCardsProgramme {
            //Mapper function
          //Reduce funtion
          //Main function
     public static void main(String[] args) throws Exception {
        Configuration config = new Configuration();
        Job job = new Job(config, "Search for list of missing Cards");
        job.setJarByClass(PokerCardsProgramme.class);
        job.setMapperClass(mapper.class);
        job.setReducerClass(reducer.class);
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(IntWritable.class);
        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));
        job.waitForCompletion(true);
       }
    }

Compiled code using - javac -classpath /home/ec2-user/hadoop_home/hadoop-1.2.1/hadoop-core-1.2.1.jar PokerCardsProgramme.java

Jar is created by using following command - jar cvf MissingPokerCards.jar PokerCardsProgramme*.class

Jar file is ran using - hadoop jar MissingPokerCards.jar MissingPokerCards.PokerCardsProgramme \input\inputcards.txt output

My Hadoop version is 1.2.1 and java version is 1.7.0_241

Even I tried using a different version of Hadoop-2-7-3

hadoop jar /home/ec2-user/hadoop/hadoop-2.7.3/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.7.3.jar MissingPokerCards.PokerCardsProgramme inputcards.txt /output

Still facing the same issue. I think I am missing the PokerCards function related jar file.

Can anybody please help me with this problem. Am I using the correct command to compile and run the program or else is there any way to execute the MissingPokerCards program on ec2 instance. I am able to run the same code in eclipse but when I tried to execute on ec2 it is showing this issue.

OneCricketeer OneCricketeer · Accepted Answer · 2020-03-08T08:10:17

The error has nothing to do with Hadoop or EC2. This is just a regular Java error. If you really want to run Hadoop code in AWS use EMR, not EC2 instances

Your package is MissingPokerCards. The error says it's finalPoker

Your class is PokerCardsProgramme. Your error says it's MissingPokerCards

FWIW, not many people actually write mapreduce nowadays, but you definitely should be using Hadoop 2 or 3 with Java 8, not 1.2.1 with Java 7

ClassNotFoundException while running MissingPokerCards on ec2 Instance

1 Answers