How can I fix NoClassDefFoundError: org/hibernate/HibernateException?

at the moment I’m developing a little program, which uses Maven and Hibernate.
I wrote 130 Junit tests. Half of them are testing my DAOs. All of them are successful and don’t make any problems.
Now I started to write some REST methods and wanted to test them with Postman. The problem is that I get an exception as response and I don’t know how to fix it.

org.jboss.resteasy.spi.UnhandledException: java.lang.NoClassDefFoundError: org/hibernate/HibernateException
    at [e-mail]//org.jboss.resteasy.core.ExceptionHandler.handleApplicationException(ExceptionHandler.java:82)
    at [e-mail]//org.jboss.resteasy.core.ExceptionHandler.handleException(ExceptionHandler.java:346)
    at [e-mail]//org.jboss.resteasy.core.SynchronousDispatcher.writeException(SynchronousDispatcher.java:193)
    at [e-mail]//org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:457)
    at [e-mail]//org.jboss.resteasy.core.SynchronousDispatcher.lambda$invoke$4(SynchronousDispatcher.java:229)
    at [e-mail]//org.jboss.resteasy.core.SynchronousDispatcher.lambda$preprocess$0(SynchronousDispatcher.java:135)
    at [e-mail]//org.jboss.resteasy.core.interception.PreMatchContainerRequestContext.filter(PreMatchContainerRequestContext.java:358)
    at [e-mail]//org.jboss.resteasy.core.SynchronousDispatcher.preprocess(SynchronousDispatcher.java:138)
    at [e-mail]//org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:215)
    at [e-mail]//org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:245)
    at [e-mail]//org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:61)
    at [e-mail]//org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
    at [e-mail]//javax.servlet.http.HttpServlet.service(HttpServlet.java:590)
    at [e-mail]//io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)
    at [e-mail]//io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
    at io.opentracing.contrib.opentracing-jaxrs2//io.opentracing.contrib.jaxrs2.server.SpanFinishingFilter.doFilter(SpanFinishingFilter.java:52)
    at [e-mail]//io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
    at [e-mail]//io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
    at [e-mail]//io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
    at [e-mail]//io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
    at [e-mail]//io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68)
    at [e-mail]//io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
    at [e-mail]//org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
    at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at [e-mail]//io.undertow.servlet.handlers.RedirectDirHandler.handleRequest(RedirectDirHandler.java:68)
    at [e-mail]//io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:132)
    at [e-mail]//io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
    at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at [e-mail]//io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
    at [e-mail]//io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
    at [e-mail]//io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
    at [e-mail]//io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
    at [e-mail]//io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
    at [e-mail]//io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
    at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at [e-mail]//org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
    at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at [e-mail]//org.wildfly.extension.undertow.deployment.GlobalRequestControllerHandler.handleRequest(GlobalRequestControllerHandler.java:68)
    at [e-mail]//io.undertow.servlet.handlers.SendErrorPageHandler.handleRequest(SendErrorPageHandler.java:52)
    at [e-mail]//io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
    at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:269)
    at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:78)
    at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:133)
    at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:130)
    at [e-mail]//io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
    at [e-mail]//io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
    at [e-mail]//org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105)
    at [e-mail]//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
    at [e-mail]//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
    at [e-mail]//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
    at [e-mail]//org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
    at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:249)
    at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:78)
    at [e-mail]//io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:99)
    at [e-mail]//io.undertow.server.Connectors.executeRootHandler(Connectors.java:387)
    at [e-mail]//io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:841)
    at [e-mail]//org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
    at [e-mail]//org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1990)
    at [e-mail]//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
    at [e-mail]//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377)
    at [e-mail]//org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1280)
    at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.lang.NoClassDefFoundError: org/hibernate/HibernateException
    at deployment.XYZ.war//com.xy.employee.dao.EmployeeDAO.createEmployee(EmployeeDAO.java:17)
    at deployment.XYZ.war//com.xy.employee.bo.EmployeeBO.createEmployee(EmployeeBO.java:25)
    at deployment.XYZ.war//com.xy.employee.service.EmployeeServiceImpl.createEmployee(EmployeeServiceImpl.java:15)
    at deployment.XYZ.war//com.xy.employee.rest.EmployeeRest.createEmployee(EmployeeRest.java:43)
    at deployment.XYZ.war//com.xy.employee.rest.EmployeeRest$Proxy$_$$_WeldClientProxy.createEmployee(Unknown Source)
    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:564)
    at [e-mail]//org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:138)
    at [e-mail]//org.jboss.resteasy.core.ResourceMethodInvoker.internalInvokeOnTarget(ResourceMethodInvoker.java:543)
    at [e-mail]//org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTargetAfterFilter(ResourceMethodInvoker.java:432)
    at [e-mail]//org.jboss.resteasy.core.ResourceMethodInvoker.lambda$invokeOnTarget$0(ResourceMethodInvoker.java:393)
    at [e-mail]//org.jboss.resteasy.core.interception.PreMatchContainerRequestContext.filter(PreMatchContainerRequestContext.java:358)
    at [e-mail]//org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:395)
    at [e-mail]//org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:364)
    at [e-mail]//org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:337)
    at [e-mail]//org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:440)
    ... 58 more
Caused by: java.lang.ClassNotFoundException: org.hibernate.HibernateException from [Module "deployment.XYZ.war" from Service Module Loader]
    at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:255)
    at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:410)
    at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398)
    at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:116)
    ... 76 more

This is my pom.xml:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.xy</groupId>
    <artifactId>XYZ</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <packaging>war</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <name>XYZ</name>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.4.22.Final</version>
        </dependency>
        <dependency>
            <groupId>org.jboss.arquillian</groupId>
            <artifactId>arquillian-bom</artifactId>
            <version>1.6.0.Final</version>
            <scope>import</scope>
            <type>pom</type>
        </dependency>
        <dependency>
            <groupId>org.jboss.arquillian.junit</groupId>
            <artifactId>arquillian-junit-container</artifactId>
            <version>1.6.0.Final</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.assertj</groupId>
            <artifactId>assertj-core</artifactId>
            <version>3.17.2</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.1</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.21</version>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.11</version>
        </dependency>
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-api</artifactId>
            <version>8.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.jboss.resteasy</groupId>
            <artifactId>resteasy-client</artifactId>
            <version>4.5.6.Final</version>
        </dependency>
        <dependency>
            <groupId>org.json</groupId>
            <artifactId>json</artifactId>
            <version>20200518</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>XYZ</finalName>
        <pluginManagement>
            <plugins>
                <plugin>
                    <artifactId>maven-clean-plugin</artifactId>
                    <version>3.1.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-resources-plugin</artifactId>
                    <version>3.0.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.0</version>
                </plugin>
                <plugin>
                    <artifactId>maven-surefire-plugin</artifactId>
                    <version>2.22.1</version>
                    <configuration>
                        <trimStackTrace>false</trimStackTrace>
                    </configuration>
                </plugin>
                <plugin>
                    <artifactId>maven-war-plugin</artifactId>
                    <version>3.2.2</version>
                    <configuration>
                        <warSourceDirectory>WebContent</warSourceDirectory>
                    </configuration>
                </plugin>
                <plugin>
                    <artifactId>maven-install-plugin</artifactId>
                    <version>2.5.2</version>
                </plugin>
                <plugin>
                    <artifactId>maven-deploy-plugin</artifactId>
                    <version>2.8.2</version>
                </plugin>
            </plugins>
        </pluginManagement>
        <plugins>
            <plugin>
                <artifactId>maven-ear-plugin</artifactId>
                <version>3.1.0</version>
                <configuration>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-ejb-plugin</artifactId>
                <version>3.1.0</version>
                <configuration>
                    <ejbVersion>3.0</ejbVersion>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Do you have any idea, how to fix this problem?

Answer

The reason of the error was an empty lib folder inside the deployment folder of wildfly.
I could solve it by doing this:
I recreated the complete project (new maven project and copyied all java files from old to new). Now all dependencies are added to the lib folder of wildfly
Looks like there was an error in the project setup