No value has been specified for property 'mainClassName' in shadowJar

Question

I am compile flink using gradle(v6.0.1) build tool like this, but show this error:

~ ⌚ 13:53:42
$ bash -c "$(curl https://flink.apache.org/q/gradle-quickstart.sh)" -- 1.10.0 2.11
~/quickstart ⌚ 14:08:22
$ ./gradlew clean shadowJar
> Task :shadowJar FAILED

FAILURE: Build failed with an exception.

* What went wrong:
A problem was found with the configuration of task ':shadowJar' (type 'ShadowJar').
> No value has been specified for property 'mainClassName'.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.0.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD FAILED in 1s
4 actionable tasks: 4 executed

this this my gradle build.gradle:

buildscript {
    repositories {
        jcenter() // this applies only to the Gradle 'Shadow' plugin
    }
    dependencies {
        classpath 'com.github.jengelman.gradle.plugins:shadow:2.0.4'
    }
}

plugins {
    id 'java'
    id 'application'
    // shadow plugin to produce fat JARs
    id 'com.github.johnrengelman.shadow' version '2.0.4'
}

apply plugin: 'application'

// artifact properties
group = 'org.myorg.quickstart'
version = '0.1-SNAPSHOT'
mainClassName = 'org.myorg.quickstart.StreamingJob'
description = """Flink Quickstart Job"""

ext {
    javaVersion = '1.8'
    flinkVersion = '1.10.0'
    scalaBinaryVersion = '2.11'
    slf4jVersion = '1.7.7'
    log4jVersion = '1.2.17'
}


sourceCompatibility = javaVersion
targetCompatibility = javaVersion
tasks.withType(JavaCompile) {
    options.encoding = 'UTF-8'
}

applicationDefaultJvmArgs = ["-Dlog4j.configuration=log4j.properties"]


// declare where to find the dependencies of your project
repositories {
    mavenCentral()
}

// NOTE: We cannot use "compileOnly" or "shadow" configurations since then we could not run code
// in the IDE or with "gradle run". We also cannot exclude transitive dependencies from the
// shadowJar yet (see https://github.com/johnrengelman/shadow/issues/159).
// -> Explicitly define the // libraries we want to be included in the "flinkShadowJar" configuration!
configurations {
    flinkShadowJar // dependencies which go into the shadowJar

    // always exclude these (also from transitive dependencies) since they are provided by Flink
    flinkShadowJar.exclude group: 'org.apache.flink', module: 'force-shading'
    flinkShadowJar.exclude group: 'com.google.code.findbugs', module: 'jsr305'
    flinkShadowJar.exclude group: 'org.slf4j'
    flinkShadowJar.exclude group: 'log4j'
}

// declare the dependencies for your production and test code
dependencies {
    // --------------------------------------------------------------
    // Compile-time dependencies that should NOT be part of the
    // shadow jar and are provided in the lib folder of Flink
    // --------------------------------------------------------------
    compile "org.apache.flink:flink-java:${flinkVersion}"
    compile "org.apache.flink:flink-streaming-java_${scalaBinaryVersion}:${flinkVersion}"

    // --------------------------------------------------------------
    // Dependencies that should be part of the shadow jar, e.g.
    // connectors. These must be in the flinkShadowJar configuration!
    // --------------------------------------------------------------
    //flinkShadowJar "org.apache.flink:flink-connector-kafka-0.11_${scalaBinaryVersion}:${flinkVersion}"

    compile "log4j:log4j:${log4jVersion}"
    compile "org.slf4j:slf4j-log4j12:${slf4jVersion}"

    // Add test dependencies here.
    // testCompile "junit:junit:4.12"
}

// make compileOnly dependencies available for tests:
sourceSets {
    main.compileClasspath += configurations.flinkShadowJar
    main.runtimeClasspath += configurations.flinkShadowJar

    test.compileClasspath += configurations.flinkShadowJar
    test.runtimeClasspath += configurations.flinkShadowJar

    javadoc.classpath += configurations.flinkShadowJar
}

run.classpath = sourceSets.main.runtimeClasspath

jar {
    manifest {
        attributes 'Built-By': System.getProperty('user.name'),
                'Build-Jdk': System.getProperty('java.version')
    }
}

shadowJar {
    configurations = [project.configurations.flinkShadowJar]
}

I am read the some answer to tell that the script do dot have mainClassName,but my config contains the mainClassName config,what should I do to fix this error? I am using macOS catalina.

Answer 1

downgrade the gradle to 4.0.1,it works.this is the gradle-wrapper.properties config:

#Mon Jan 06 13:52:34 CST 2020
distributionUrl=https\://services.gradle.org/distributions/gradle-4.0.1-all.zip
distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStorePath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME

this is the build command:

~/quickstart ⌚ 14:48:25
$ ./gradlew clean shadowJar
Downloading https://services.gradle.org/distributions/gradle-4.0.1-all.zip
........10%.........20%........30%.........40%........50%.........60%.........70%........80%.........90%........100%
Starting a Gradle Daemon (subsequent builds will be faster)

BUILD SUCCESSFUL in 1m 46s
4 actionable tasks: 4 executed

maybe help you.