How to submit Spark job through containerized Livy

I'm using the following repo to run Spark (2.4.7) and Livy (0.7).

The curl commands shown on the repo works fine, and it seems that everything is up and running.

I wrote a simple word counting maven Spark Java program and used Livy client to submit it as a Spark job through Livy.

My Java word counting:

package spark;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.regex.Pattern;
import org.apache.spark.api.java.*;
import org.apache.spark.api.java.function.*;
import org.apache.livy.Job;
import org.apache.livy.JobContext;
import scala.Tuple2;

public final class JavaWordCount implements Job<Double> {

    private static final long serialVersionUID = 4870271814150948504L;
    private static final Pattern SPACE = Pattern.compile(" ");

    @Override
    public Double call(JobContext ctx) throws Exception {
        count(ctx);
        return 0.7;
    }

    public void count(JobContext ctx){

        //JavaRDD<String> lines = ctx.textFile(args[0], 1);
        JavaRDD<String> lines = ctx.sc().parallelize(Arrays.asList("It is close to midnight and something evil is lurking in the dark".split(" ")));


        JavaRDD<String> words = lines.flatMap(new FlatMapFunction<String, String>() {
            @Override
            public Iterator<String> call(String s) {
                return 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());
        }
    }
}

My Livy client:

package spark;

import org.apache.livy.Job;
import org.apache.livy.LivyClient;
import org.apache.livy.LivyClientBuilder;

import java.io.File;
import java.net.URI;

public final class SubmitJob {

    private static final String livyURI = "http://localhost:8998/";
    private static final String JAR_PATH = "/Users/.../spark-word-count/target/word-count-0.1-SNAPSHOT.jar";

    public static void main(String[] args) throws Exception {
        LivyClient livyClient = new LivyClientBuilder()
        .setURI(new URI(livyURI)).build();
        
        try {
            System.err.printf("Uploading %s to the Spark context...\n", JAR_PATH);
            livyClient.uploadJar(new File(JAR_PATH));
            
            System.err.printf("Running JavaWordCount...\n", JAR_PATH);
            double pi = livyClient.submit(new JavaWordCount()).get();
        
            System.out.println("Pi is roughly: " + pi);
        } finally {
            livyClient.stop(true);
        }

    }
}

When I run my client I get the following error:

Exception in thread "main" java.util.concurrent.ExecutionException: java.lang.RuntimeException: org.apache.livy.shaded.kryo.kryo.KryoException: Unable to find class: spark.JavaWordCount at org.apache.livy.shaded.kryo.kryo.util.DefaultClassResolver.readName(DefaultClassResolver.java:138) at org.apache.livy.shaded.kryo.kryo.util.DefaultClassResolver.readClass(DefaultClassResolver.java:115)

Exception in thread "main" java.util.concurrent.ExecutionException: java.lang.RuntimeException: org.apache.livy.shaded.kryo.kryo.KryoException: Unable to find class: spark.JavaWordCount at org.apache.livy.shaded.kryo.kryo.util.DefaultClassResolver.readName(DefaultClassResolver.java:138) at org.apache.livy.shaded.kryo.kryo.util.DefaultClassResolver.readClass(DefaultClassResolver.java:115) at org.apache.livy.shaded.kryo.kryo.Kryo.readClass(Kryo.java:656) at org.apache.livy.shaded.kryo.kryo.Kryo.readClassAndObject(Kryo.java:767) at org.apache.livy.client.common.Serializer.deserialize(Serializer.java:63) at org.apache.livy.rsc.driver.BypassJob.call(BypassJob.java:39) at org.apache.livy.rsc.driver.BypassJob.call(BypassJob.java:27) at org.apache.livy.rsc.driver.JobWrapper.call(JobWrapper.java:64) at org.apache.livy.rsc.driver.BypassJobWrapper.call(BypassJobWrapper.java:45) at org.apache.livy.rsc.driver.BypassJobWrapper.call(BypassJobWrapper.java:27) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.ClassNotFoundException: spark.JavaWordCount

How can I solve this error?

I read it might be because of livy.file.local-dir-whitelist. My Livy conf whitelist looks like this:

livy.file.local-dir-whitelist = /

I have tried to upload the Jar to the Livy container and put it under "/", and changed the JAR_PATH = "/word-count-0.1-SNAPSHOT.jar" on my client. I getting the same error...

How can I submit my Jar?