Unable to initialize 'javax.el.ExpressionFactory' in reactive testing

Question

I am using spring boot and my POM looks like this :

<properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>


    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb-reactive</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>de.flapdoodle.embed</groupId>
            <artifactId>de.flapdoodle.embed.mongo</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.8</version>
        </dependency>

    </dependencies>


    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>


        </plugins>
    </build>

but only when I'm testing but testing is working so this is not influence testing yet this is unusual , when I do normally run spring application everything is fine

public class CategoryControllerTest {

        WebTestClient webTestClient;
        CategoryRepository categoryRepository;
        CategoryController categoryController;


        @Before
        public void setUp() throws Exception {
            categoryRepository = Mockito.mock(CategoryRepository.class);
            categoryController = new CategoryController(categoryRepository);
            webTestClient = WebTestClient.bindToController(categoryController).build();
        }

        @Test
        public void list() {
            BDDMockito.given(categoryRepository.findAll())
                    .willReturn(Flux.just(Category.builder().description("Cat1").build(),
                            Category.builder().description("Cat2").build()));

            webTestClient.get()
                    .uri("/api/v1/categories/")
                    .exchange()
                    .expectBodyList(Category.class)
                    .hasSize(2);
        }
        @Test
        public void getById() {
            BDDMockito.given(categoryRepository.findById(anyString()))
                    .willReturn(Mono.just(Category.builder().description("cat").build()));

            webTestClient.get()
                    .uri("/api/v1/categories/someid")
                    .exchange()
                    .expectBody(Category.class);
        }
    }

In line with webTestClient = WebTestClient.bindToController(categoryController).build(); I've got an error and I don't know why hibernate is launching and is giving me this error even though I'm using mongodb

error stack:

15:59:52.364 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'webFluxValidator'
15:59:52.455 [main] DEBUG org.jboss.logging - Logging Provider: org.jboss.logging.Log4j2LoggerProvider
15:59:52.457 [main] INFO org.hibernate.validator.internal.util.Version - HV000001: Hibernate Validator 6.0.16.Final
15:59:52.467 [main] DEBUG org.hibernate.validator.internal.engine.resolver.TraversableResolvers - Cannot find javax.persistence.Persistence on classpath. Assuming non JPA 2 environment. All properties will per default be traversable.
15:59:52.488 [main] DEBUG org.springframework.validation.beanvalidation.OptionalValidatorFactoryBean - Failed to set up a Bean Validation provider
javax.validation.ValidationException: HV000183: Unable to initialize 'javax.el.ExpressionFactory'. Check that you have the EL dependencies on the classpath, or use ParameterMessageInterpolator instead
    at org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator.buildExpressionFactory(ResourceBundleMessageInterpolator.java:116)
    at org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator.<init>(ResourceBundleMessageInterpolator.java:47)
    at org.hibernate.validator.internal.engine.ConfigurationImpl.getDefaultMessageInterpolator(ConfigurationImpl.java:474)
    at org.springframework.validation.beanvalidation.LocalValidatorFactoryBean.afterPropertiesSet(LocalValidatorFactoryBean.java:272)
    at org.springframework.validation.beanvalidation.OptionalValidatorFactoryBean.afterPropertiesSet(OptionalValidatorFactoryBean.java:40)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1837)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1774)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.resolveBeanReference(ConfigurationClassEnhancer.java:394)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:366)
    at org.springframework.web.reactive.config.DelegatingWebFluxConfiguration$$EnhancerBySpringCGLIB$$2dc2c1f3.webFluxValidator(<generated>)
    at org.springframework.web.reactive.config.WebFluxConfigurationSupport.getConfigurableWebBindingInitializer(WebFluxConfigurationSupport.java:331)
    at org.springframework.web.reactive.config.WebFluxConfigurationSupport.requestMappingHandlerAdapter(WebFluxConfigurationSupport.java:271)
    at org.springframework.web.reactive.config.DelegatingWebFluxConfiguration$$EnhancerBySpringCGLIB$$2dc2c1f3.CGLIB$requestMappingHandlerAdapter$26(<generated>)
    at org.springframework.web.reactive.config.DelegatingWebFluxConfiguration$$EnhancerBySpringCGLIB$$2dc2c1f3$$FastClassBySpringCGLIB$$44112402.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:363)
    at org.springframework.web.reactive.config.DelegatingWebFluxConfiguration$$EnhancerBySpringCGLIB$$2dc2c1f3.requestMappingHandlerAdapter(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:622)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:456)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1321)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1160)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:602)
    at org.springframework.context.support.AbstractApplicationContext.getBeansOfType(AbstractApplicationContext.java:1234)
    at org.springframework.beans.factory.BeanFactoryUtils.beansOfTypeIncludingAncestors(BeanFactoryUtils.java:340)
    at org.springframework.web.reactive.DispatcherHandler.initStrategies(DispatcherHandler.java:128)
    at org.springframework.web.reactive.DispatcherHandler.setApplicationContext(DispatcherHandler.java:116)
    at org.springframework.context.support.ApplicationContextAwareProcessor.invokeAwareInterfaces(ApplicationContextAwareProcessor.java:120)
    at org.springframework.context.support.ApplicationContextAwareProcessor.postProcessBeforeInitialization(ApplicationContextAwareProcessor.java:96)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:414)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1770)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$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:849)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:877)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549)
    at org.springframework.test.web.reactive.server.DefaultControllerSpec.initApplicationContext(DefaultControllerSpec.java:143)
    at org.springframework.test.web.reactive.server.DefaultControllerSpec.initHttpHandlerBuilder(DefaultControllerSpec.java:128)
    at org.springframework.test.web.reactive.server.AbstractMockServerSpec.configureClient(AbstractMockServerSpec.java:86)
    at org.springframework.test.web.reactive.server.AbstractMockServerSpec.build(AbstractMockServerSpec.java:107)
    at org.czekalski.spring5webfluxrest.controllers.CategoryControllerTest.setUp(CategoryControllerTest.java:30)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.lang.NoClassDefFoundError: javax/el/ELManager
    at org.hibernate.validator.messageinterpolation.ResourceBundleMessageInterpolator.buildExpressionFactory(ResourceBundleMessageInterpolator.java:108)
    ... 82 common frames omitted
Caused by: java.lang.ClassNotFoundException: javax.el.ELManager
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 83 common frames omitted
15:59:52.490 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'webFluxAdapterRegistry'
15:59:52.670 [main] DEBUG org.springframework.web.reactive.result.method.annotation.ControllerMethodResolver - ControllerAdvice beans: none

Answer 1

Please add below dependencies:

<dependency>
  <groupId>org.glassfish</groupId>
  <artifactId>javax.el</artifactId>
  <version>3.0.0</version>
</dependency>
<dependency>
  <groupId>javax.el</groupId>
  <artifactId>javax.el-api</artifactId>
  <version>3.0.0</version>
</dependency>

Hibernate Validator also requires an implementation of the Unified Expression Language (JSR 341) for evaluating dynamic expressions in constraint violation messages. In a Java SE environment, you have to add an implementation as dependency to your POM file.

Answer 2

This is an exception from hibernate-validator - the validation library that has (almost) nothing to do with the database connectivity. It's a transitive dependency of some library that you included into your project (you can run mvn dependency:tree to determine which).

Try to add the javax.el-api dependency that the stacktrace error asks for.

If your project depends on Hibernate Validator 5.x:

<dependency>
  <groupId>javax.el</groupId>
  <artifactId>javax.el-api</artifactId>
  <version>2.2.5</version>
</dependency>

Hibernate Validator 6.x:

<dependency>
  <groupId>javax.el</groupId>
  <artifactId>javax.el-api</artifactId>
  <version>3.0.0</version>
</dependency>