Gradle multi module project java.lang.NoClassDeffFoundError

Question

i have the following simple test-project-structure

 |TestProject
 |
 |---project-a
 |   |---src
 |       |---main
 |           |---java
 |               |---package-name.ProjectA
 |                   |---service
 |                   |   |---TestService.java
 |                   |
 |                   |---ProjectAServiceApplication.java
 |
 |---project-b
 |   |---src
 |       |---main
 |           |---java
 |               |---package-name.ProjectB
 |                   |---enums
 |                       |---Commodity.java
 |
 |---build.gradle
 |---settings.gradle

The build.gradle looks like

import com.commercehub.gradle.plugin.avro.GenerateAvroJavaTask
import groovy.json.*

buildscript {
    ext {
        springCloudVersion =  'Greenwich.RELEASE'
        springBootVersion =  '2.1.2.RELEASE'
    }

    repositories {
        mavenCentral()
        jcenter()
        maven {
            url "http://packages.confluent.io/maven"
        }
        maven { url 'https://repo.spring.io/milestone' }
        maven { url 'https://projectlombok.org/edge-releases' }

    }
    dependencies {
        classpath "org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}"
        classpath "com.commercehub.gradle.plugin:gradle-avro-plugin:0.14.2"
        classpath "net.ltgt.gradle:gradle-apt-plugin:0.21"
    }
}

plugins {
    id "net.ltgt.apt" version "0.21" apply false
    id "io.spring.dependency-management" version "1.0.8.RELEASE"
}

subprojects {

    // Packer variables
    ext {
        packerVariablesFolder = "$buildDir/packer"
        packerVariablesPath = "$packerVariablesFolder/$packerVariables"
        packerTemplateFolder = "../config"
        packerTemplatePath = "$packerTemplateFolder/$packerTemplate"
    }

    apply plugin: 'idea'
    apply plugin: 'io.spring.dependency-management'
    apply plugin: 'java'
    apply plugin: 'java-library'
    apply plugin: 'org.springframework.boot'

    group = 'de.SWS.PLM'
    version = '0.0.1-SNAPSHOT'
    sourceCompatibility = '11'

    repositories {
        mavenCentral()
        jcenter()
        maven {
            url "http://packages.confluent.io/maven"
        }
        maven { url 'https://repo.spring.io/milestone' }
        maven { url 'https://projectlombok.org/edge-releases' }
    }

    springBoot {
        buildInfo()
    }

    dependencyManagement {
        imports {
            mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
        }
    }

    ext.convertProjectName = { ->
        return project.name.split("(?<!(^|[A-Z]))(?=[A-Z])|(?<!^)(?=[A-Z][a-z])").join("-").toLowerCase()
    }

    dependencies {
        implementation 'org.springframework.boot:spring-boot-starter-actuator'
        compile group: 'log4j', name: 'log4j', version: '1.2.17'
        compile 'org.apache.commons:commons-lang3:3.10'
        compileOnly 'org.projectlombok:lombok:1.18.10'
        annotationProcessor 'org.projectlombok:lombok:1.18.10'
        testImplementation 'org.springframework.boot:spring-boot-starter-test'
    }

    task defineBuildVersion {
        if (project.hasProperty("revision")) {
            ext.imageVersion = version + "-${revision}"
        } else {
            ext.imageVersion = version + "-SNAPSHOT"
        }
    }

    compileJava {
        //raise heap
        options.fork = 'true'
        options.forkOptions.with {
            memoryMaximumSize = '2048m'
        }
    }

    task generatePackerFiles {
        doLast {
            mkdir "$packerVariablesFolder"
            new File("$packerVariablesPath").text = JsonOutput.toJson([
                    jar_file: jar.archiveName,
                    logback_file: "logback-pfm.xml",
                    image_name: "$convertProjectName",
                    image_tag: "${defineBuildVersion.imageVersion}"
            ])
        }
    }

    task buildDockerImage(type: Exec) {
        dependsOn generatePackerFiles
        commandLine 'packer', 'build', "-var-file=${packerVariablesPath}", "${packerTemplatePath}"
    }

    compileJava {
        //raise heap
        options.fork = 'true'
        options.forkOptions.with {
            memoryMaximumSize = '2048m'
        }
    }

    task cleanIntellijDirs(type: Delete) {
        delete 'out'
    }
}

configure(subprojects.findAll { !['project-b'].contains(it.name)} ) {
    dependencies {
        implementation project(':project-b')
    }
}

and the settings.gradle looks like

rootProject.name = 'TestProject'

include 'project-a'
include 'project-b'

If i run the gradlew task build for project-a gradle :project-a:build it builds the project correctly and generate a *.jar file. If i execute the *.jar file i get the following output

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'testService' defined in URL [jar:file:/C:/Users/sws-216/Documents/Projekte/pfm-project/TestProject/project-a/build/libs/project-a-0.0.1-SNAPSHOT.jar!/BOOT-INF/classes!/de/SWS/PLM/ProjectA/service/TestService.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [de.SWS.PLM.ProjectA.service.TestService]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: de/SWS/PLM/Commodity
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1270) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1164) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:846) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863) ~[spring-context-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546) ~[spring-context-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) ~[spring-boot-2.1.2.RELEASE.jar!/:2.1.2.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.1.2.RELEASE.jar!/:2.1.2.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) ~[spring-boot-2.1.2.RELEASE.jar!/:2.1.2.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) ~[spring-boot-2.1.2.RELEASE.jar!/:2.1.2.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) ~[spring-boot-2.1.2.RELEASE.jar!/:2.1.2.RELEASE]
        at de.SWS.PLM.ProjectA.ProjectAServiceApplication.main(ProjectAServiceApplication.java:10) ~[classes!/:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
        at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) ~[project-a-0.0.1-SNAPSHOT.jar:na]
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) ~[project-a-0.0.1-SNAPSHOT.jar:na]
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) ~[project-a-0.0.1-SNAPSHOT.jar:na]
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) ~[project-a-0.0.1-SNAPSHOT.jar:na]
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [de.SWS.PLM.ProjectA.service.TestService]: Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: de/SWS/PLM/Commodity
        at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:184) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1262) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        ... 24 common frames omitted
Caused by: java.lang.NoClassDefFoundError: de/SWS/PLM/Commodity
        at de.SWS.PLM.ProjectA.service.TestService.<init>(TestService.java:12) ~[classes!/:na]
        at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
        at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[na:na]
        at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:172) ~[spring-beans-5.1.4.RELEASE.jar!/:5.1.4.RELEASE]
        ... 26 common frames omitted
Caused by: java.lang.ClassNotFoundException: de.SWS.PLM.Commodity
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471) ~[na:na]
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:589) ~[na:na]
        at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:93) ~[project-a-0.0.1-SNAPSHOT.jar:na]
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522) ~[na:na]
        ... 32 common frames omitted

What i do wrong setting up the gradle multi modules project?

Answer 1

Ok, i do the following

add

jar {
    enabled = true
}

bootJar {
    classifier = 'boot'
}

to my project-a. Then build it and received two *.jars. I Included the boot.jar one into my dockerfile and deployed it. Unfortunately i get the same error

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
22-07-2020 08:05:01.610 ERROR org.springframework.boot.SpringApplication.reportFailure - Application run failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'priceService': Lookup method resolution failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [de.SWS.PLM.PriceParseService.services.PriceService] from ClassLoader [org.springframework.boot.loader.LaunchedURLClassLoader@7225790e]
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.determineCandidateConstructors(AutowiredAnnotationBeanPostProcessor.java:265)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineConstructorsFromBeanPostProcessors(AbstractAutowireCapableBeanFactory.java:1236)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1151)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498)
        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:846)
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775)
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:316)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
        at de.SWS.PLM.PriceParseService.PriceParseServiceApplication.main(PriceParseServiceApplication.java:17)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51)
Caused by: java.lang.IllegalStateException: Failed to introspect Class [de.SWS.PLM.PriceParseService.services.PriceService] from ClassLoader [org.springframework.boot.loader.LaunchedURLClassLoader@7225790e]
        at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:686)
        at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:583)
        at org.springframework.util.ReflectionUtils.doWithMethods(ReflectionUtils.java:568)
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.determineCandidateConstructors(AutowiredAnnotationBeanPostProcessor.java:248)
        ... 26 common frames omitted
Caused by: java.lang.NoClassDefFoundError: de/SWS/PLM/utils/ExcelCellTypeError
        at java.base/java.lang.Class.getDeclaredMethods0(Native Method)
        at java.base/java.lang.Class.privateGetDeclaredMethods(Class.java:3166)
        at java.base/java.lang.Class.getDeclaredMethods(Class.java:2309)
        at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:668)
        ... 29 common frames omitted
Caused by: java.lang.ClassNotFoundException: de.SWS.PLM.utils.ExcelCellTypeError
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:589)
        at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:93)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
        ... 33 common frames omitted

If i check the structure of the boot.jar it looks like

BOOT-INF
|
|---classes
|   |---package.name
|       |---project-a
|           |---all the classes without the classes of project-b
|---lib
META-INF
org

So in both jars there are not the classes of project-b so project-a can not find the classes i think

Answer 2

The issue is in the way you are packaging project-b. You are relying on it as both a library (because you are depending on it from project-a) and as a stand-alone executable jar. But you can't use the same jar file for both these use-cases.

When you apply the Spring Boot plugin, it will by default disable the normal jar task and instead produce a "fat" jar with all dependencies bundled up, but also arranged in a way that a normal Java program can no longer find classes in it. To re-enable the original jar task, and rename the fat jar as it has the same name, do this:

jar {
    enabled = true
}

bootJar {
    classifier = 'boot'
}

When you do this, you will get two jar files on build. One is for when you use it as a normal dependency, and the other is for executing it.

I assume the reason it works in IntelliJ without this is because you are either not delegating your tasks to Gradle, or you are running it through bootRun. Both approaches will not build and run the final executable jar, but rather just use the compiled classes in an exploded form.

Sometimes, a better design is to extract the classes which are common to both project-a and project-b into a shared utility project instead of bundling an entire application inside another application (and sometimes this is what you want of cause). But you will need to do the same configuration for this as the above if you apply the Spring Boot plugin on it, which you might do for the reaction to the dependency-management plugin.

You can find more information on this in the documentation for the documentation for the Spring Boot Gradle plugin under Packaging Executable and Normal Archives.