gradle with openjdk 14 Unsupported class file major version 58

Question

I am trying to run a gradle 6.3 build using openjdk 14, targeting java 14. I get the following error. I understand it's something related to the version of the compilation file but my understanding is that gradle 6.3 supports java 14.

$ ./gradlew build
> Task :shadowJar FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':shadowJar'.
> Unsupported class file major version 58

$ ./gradlew -v

------------------------------------------------------------
Gradle 6.3
------------------------------------------------------------

Build time:   2020-03-24 19:52:07 UTC
Revision:     bacd40b727b0130eeac8855ae3f9fd9a0b207c60

Kotlin:       1.3.70
Groovy:       2.5.10
Ant:          Apache Ant(TM) version 1.10.7 compiled on September 1 2019
JVM:          14 (Oracle Corporation 14+36-1461)
OS:           Windows 10 10.0 amd64

$ java --version
openjdk 14 2020-03-17
OpenJDK Runtime Environment (build 14+36-1461)
OpenJDK 64-Bit Server VM (build 14+36-1461, mixed mode, sharing)

plugins {
    id "net.ltgt.apt-eclipse" version "0.21"
    id "com.github.johnrengelman.shadow" version "5.0.0"
    id "application"
}



version "0.1"
group "com.xyz"

sourceCompatibility = 14
targetCompatibility = 14

repositories {
    mavenCentral()
    maven { url "https://jcenter.bintray.com" }
}

configurations {
    // for dependencies that are needed for development only
    developmentOnly 
}

dependencies {
    annotationProcessor platform("io.micronaut:micronaut-bom:$micronautVersion")
    compileOnly group: 'org.projectlombok', name: 'lombok', version: '1.18.12'
    annotationProcessor group: 'org.projectlombok', name: 'lombok', version: '1.18.12'
    annotationProcessor "io.micronaut:micronaut-inject-java"
    annotationProcessor "io.micronaut:micronaut-validation"
    annotationProcessor("io.micronaut.data:micronaut-data-processor:1.0.2")
    annotationProcessor("io.micronaut.configuration:micronaut-openapi:1.4.3")
    implementation platform("io.micronaut:micronaut-bom:$micronautVersion")
    implementation "io.micronaut:micronaut-inject"
    implementation "io.micronaut:micronaut-validation"
    implementation "io.micronaut:micronaut-runtime"
    implementation "javax.annotation:javax.annotation-api"
    implementation "io.micronaut:micronaut-http-server-netty"
    implementation "io.micronaut:micronaut-http-client"
    implementation("io.micronaut.data:micronaut-data-hibernate-jpa:1.0.2")
    implementation "org.springframework.security:spring-security-crypto:$springSecurityCryptoVersion"
    implementation("io.swagger.core.v3:swagger-annotations")
    runtimeOnly "ch.qos.logback:logback-classic:1.2.3"
    compile group: 'commons-logging', name: 'commons-logging', version: '1.2'
//    compile group: 'io.micronaut.configuration', name: 'micronaut-hibernate-jpa', version: '1.3.0.RC1'
    compile "io.micronaut.configuration:micronaut-jdbc-hikari"
    compile group: 'org.postgresql', name: 'postgresql', version: '42.2.6'
//    compile 'io.micronaut.configuration:micronaut-security-oauth2:1.2.0'
//    annotationProcessor "io.micronaut:micronaut-security"
    compile "io.micronaut:micronaut-security-jwt"
    compile 'io.micronaut.configuration:micronaut-flyway'





    testAnnotationProcessor platform("io.micronaut:micronaut-bom:$micronautVersion")
    testAnnotationProcessor "io.micronaut:micronaut-inject-java"
    testImplementation "org.junit.jupiter:junit-jupiter-api"
    testImplementation "io.micronaut.test:micronaut-test-junit5"
    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine"
    testCompile group: 'org.mockito', name: 'mockito-core', version: '3.0.0'
    testCompile group: 'org.mockito', name: 'mockito-junit-jupiter', version: '3.0.0'

}

test.classpath += configurations.developmentOnly

mainClassName = "com.vdt.salv.Application"

// use JUnit 5 platform
test {
    useJUnitPlatform()
}

tasks.withType(JavaCompile){
    options.encoding = "UTF-8"
    options.compilerArgs.add('-parameters')
}


shadowJar {
    mergeServiceFiles()
}

run.classpath += configurations.developmentOnly
run.jvmArgs('-noverify', '-XX:TieredStopAtLevel=1', '-Dcom.sun.management.jmxremote')

task stage(dependsOn: ['build', 'clean'])
build.mustRunAfter clean

tasks.withType(JavaCompile) {
    options.fork = true
    options.forkOptions.jvmArgs << '-Dmicronaut.openapi.views.spec=rapidoc.enabled=true,swagger-ui.enabled=true,swagger-ui.theme=flattop'
}

micronautVersion=1.3.4
org.gradle.caching=true
springSecurityCryptoVersion=5.3.1.RELEASE

java.runtime.version=14

Answer 1

After you posted your build.gradle, I noticed you had the following plugin:

id "com.github.johnrengelman.shadow" version "5.0.0"

I looked up the Gradle plugin page, and noticed that the latest version is 5.2.0.

Updating to the latest version should fix your issue.