Getting class not found error with Gradle jar

Question

I'm new to Gradle and built a Jar build using Gradle. When I tried executing that jar using spark-submit, I'm getting a Class Not Found error. I'm able to execute the same application in IntelliJ IDEA, but getting error when executing as Independent JAR.

Below are the contents of build.gradle:

/*
 * This file was generated by the Gradle 'init' task.
 */

apply plugin: 'scala'
apply plugin: 'idea'
apply plugin: 'org.sonarqube'


// Applying Sonar Qube details for gradle
apply from: "${rootProject.rootDir}/gradle/sonar.gradle"

repositories {
    mavenLocal()
    mavenCentral()
    maven {
        url = uri('https://repo1.maven.org/maven2')
    }
}

dependencies {
    implementation 'com.google.code.gson:gson:2.8.2'
    implementation 'io.netty:netty-all:4.1.42.Final'
    implementation 'com.github.jengelman.gradle.plugins:shadow:4.0.1'
    testImplementation "org.scalatest:scalatest_2.11:$scalaTestVersion"
    runtime "com.apple.jvm.commons:commons-metrics:0.13.1"
}

buildscript {
    dependencies {
        classpath 'org.sonarsource.scanner.gradle:sonarqube-gradle-plugin:2.6'
    }
}

sourceSets {
    main {
        scala {
            srcDirs = ['src/main/scala']
        }
    }

    test {
        scala.srcDirs = ['src/test/scala']
    }
}

sonarqube {
    properties {
        property "sonar.projectName", "App-name"
        property "sonar.projectKey", "App-name"
        property "sonar.sourceEncoding", "UTF-8"
        property "sonar.tests", "src/test"
        property "sonar.sources", "src/main"
        property "sonar.scala.coverage.reportPaths", "$buildDir/reports/scoverage/scoverage.xml"
        property "sonar.coverage.jacoco.xmlReportPaths", "$buildDir/jacoco/jacoco.xml"
        property "sonar.test.exclusions", "src/test/**"
    }
}

configurations {
    jars
}

// Force Jacksom-module version to handle below error.
//com.fasterxml.jackson.databind.JsonMappingException: Scala module 2.8.8 requires Jackson Databind version >= 2.8.0 and < 2.9.0
configurations.all {
    resolutionStrategy {
        force "com.fasterxml.jackson.module:jackson-module-scala_2.11:2.9.5"
    }
}

jar {
    manifest {
        attributes(
                'Class-Path': configurations.compile.files.collect {"$it.name"}.join(' '),
                'Main-Class': 'com.github.MainClass'
        )}
    from {
        files(sourceSets.main.output.classesDirs)
        configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
        configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
    }{
        exclude "META-INF/*.SF"
        exclude "META-INF/*.DSA"
        exclude "META-INF/*.RSA"
    }
    zip64 true
    archiveClassifier = 'jar-with-dependencies'
}
/*task fatJar(type: Jar) {
    //manifest.from jar.manifest
    manifest {
        attributes 'Main-Class': 'com.github.MainClass'
    }
    zip64 true
    archiveClassifier = 'jar-with-dependencies'
    from files(sourceSets.main.output.classesDirs)
    from {
        configurations.runtime.asFileTree.files.collect {zipTree(it) }
        configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
        configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
    } {
        exclude "META-INF/*.SF"
        exclude "META-INF/*.DSA"
        exclude "META-INF/*.RSA"
    }
    with jar
}

artifacts {
    archives fatJar
}*/

I tried building the Jar with both ./gradlew clean build and ./gradlew clean fatJar and executing below command:

spark-submit --master local --deploy-mode client --class com.github.MainClass /local_path/.out/libs/App-name-1.0-SNAPSHOT-jar-with-dependencies.jar

Error:

java.lang.ClassNotFoundException: com.github.MainClass
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.apache.spark.util.Utils$.classForName(Utils.scala:238)
    at org.apache.spark.deploy.SparkSubmit.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:810)
    at org.apache.spark.deploy.SparkSubmit.doRunMain$1(SparkSubmit.scala:167)
    at org.apache.spark.deploy.SparkSubmit.submit(SparkSubmit.scala:195)
    at org.apache.spark.deploy.SparkSubmit.doSubmit(SparkSubmit.scala:86)
    at org.apache.spark.deploy.SparkSubmit$$anon$2.doSubmit(SparkSubmit.scala:924)
    at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:933)
    at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
2020-12-02 13:02:49 INFO  ShutdownHookManager:54 - Shutdown hook called
2020-12-02 13:02:49 INFO  ShutdownHookManager:54 - Deleting directory /private/var/folders/sq/npjk1mkn7lgfm57mf9g_3rrh0000gn/T/spark-8ab912b5-23ef-4182-9c70-947f2cd2831a