KafkaMessageChannelBinder cannot be cast to class TestSupportBinder

Question

In our project we are using the spring-cloud-starter-stream-kafka for consuming the messages from Kafka, after adding the @ComponentScan for "org.springframework.cloud.stream.binder.kafka" package, the integration tests started failing with the following exception

Failed to load ApplicationContext
java.lang.IllegalStateException: Failed to load ApplicationContext
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:132)
    at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:124)
    at org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener.postProcessFields(MockitoTestExecutionListener.java:110)
    at org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener.injectFields(MockitoTestExecutionListener.java:94)
    at org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener.prepareTestInstance(MockitoTestExecutionListener.java:61)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:248)
    at org.springframework.test.context.junit.jupiter.SpringExtension.postProcessTestInstance(SpringExtension.java:138)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$8(ClassBasedTestDescriptor.java:363)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.executeAndMaskThrowable(ClassBasedTestDescriptor.java:368)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeTestInstancePostProcessors$9(ClassBasedTestDescriptor.java:363)
    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
    at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
    at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
    at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:312)
    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:735)
    at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.invokeTestInstancePostProcessors(ClassBasedTestDescriptor.java:362)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$instantiateAndPostProcessTestInstance$6(ClassBasedTestDescriptor.java:283)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.instantiateAndPostProcessTestInstance(ClassBasedTestDescriptor.java:282)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$4(ClassBasedTestDescriptor.java:272)
    at java.base/java.util.Optional.orElseGet(Optional.java:362)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$5(ClassBasedTestDescriptor.java:271)
    at org.junit.jupiter.engine.execution.TestInstancesProvider.getTestInstances(TestInstancesProvider.java:31)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$before$2(ClassBasedTestDescriptor.java:197)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.before(ClassBasedTestDescriptor.java:196)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.before(ClassBasedTestDescriptor.java:80)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:148)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:108)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:96)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:75)
    at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:99)
    at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$000(JUnitPlatformTestClassProcessor.java:79)
    at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:75)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:61)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
    at com.sun.proxy.$Proxy5.stop(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker$3.run(TestWorker.java:193)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:129)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:100)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:60)
    at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56)
    at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:133)
    at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:71)
    at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69)
    at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageCollector' defined in class path resource [org/springframework/cloud/stream/test/binder/MessageCollectorAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.stream.test.binder.MessageCollector]: Factory method 'messageCollector' threw exception; nested exception is java.lang.ClassCastException: class org.springframework.cloud.stream.binder.kafka.KafkaMessageChannelBinder cannot be cast to class org.springframework.cloud.stream.test.binder.TestSupportBinder (org.springframework.cloud.stream.binder.kafka.KafkaMessageChannelBinder and org.springframework.cloud.stream.test.binder.TestSupportBinder are in unnamed module of loader 'app')
    at app//org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658)
    at app//org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:638)
    at app//org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352)
    at app//org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195)
    at app//org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582)
    at app//org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)
    at app//org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)
    at app//org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
    at app//org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)
    at app//org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)
    at app//org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:953)
    at app//org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918)
    at app//org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)
    at app//org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)
    at app//org.springframework.boot.SpringApplication.refresh(SpringApplication.java:740)
    at app//org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:415)
    at app//org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
    at app//org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:136)
    at app//org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
    at app//org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)
    ... 79 more
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.stream.test.binder.MessageCollector]: Factory method 'messageCollector' threw exception; nested exception is java.lang.ClassCastException: class org.springframework.cloud.stream.binder.kafka.KafkaMessageChannelBinder cannot be cast to class org.springframework.cloud.stream.test.binder.TestSupportBinder (org.springframework.cloud.stream.binder.kafka.KafkaMessageChannelBinder and org.springframework.cloud.stream.test.binder.TestSupportBinder are in unnamed module of loader 'app')
    at app//org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
    at app//org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653)
    ... 98 more
Caused by: java.lang.ClassCastException: class org.springframework.cloud.stream.binder.kafka.KafkaMessageChannelBinder cannot be cast to class org.springframework.cloud.stream.test.binder.TestSupportBinder (org.springframework.cloud.stream.binder.kafka.KafkaMessageChannelBinder and org.springframework.cloud.stream.test.binder.TestSupportBinder are in unnamed module of loader 'app')
    at org.springframework.cloud.stream.test.binder.MessageCollectorAutoConfiguration.messageCollector(MessageCollectorAutoConfiguration.java:35)
    at org.springframework.cloud.stream.test.binder.MessageCollectorAutoConfiguration$$EnhancerBySpringCGLIB$$761ac188.CGLIB$messageCollector$0(<generated>)
    at org.springframework.cloud.stream.test.binder.MessageCollectorAutoConfiguration$$EnhancerBySpringCGLIB$$761ac188$$FastClassBySpringCGLIB$$5251d9eb.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331)
    at org.springframework.cloud.stream.test.binder.MessageCollectorAutoConfiguration$$EnhancerBySpringCGLIB$$761ac188.messageCollector(<generated>)
    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 org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
    ... 99 more

The depedencies we are using

• spring-cloud-stream:3.1.4
• spring-cloud-starter-stream-kafka:3.1.4
• spring-boot-starter-test
• spring-kafka-test
• spring-cloud-stream-test-support

Answer 1

As mentioned here

The usage of spring-cloud-stream-test-support is discouraged in the 3.0.x versions of Spring Cloud Stream. The recommended artifact for testing message channel based binders is the new Spring Integration based test binder. With this new test binder, you no longer need the legacy spring-cloud-stream-test-support binder.

If you must use the old test binder (spring-cloud-stream-test-binder), then you have to isolate the Kafka Streams specific tests to a test class and then exclude the TestSupportBinderAutoConfiguration.

If the old test binder is in the classpath (spring-cloud-stream-test-support), try any of the following options

to avoid trying to bind Kafka Streams components to that binder which results in an exception thrown in the logs.

   @EnableAutoConfiguration(exclude = TestSupportBinderAutoConfiguration.class)

Or the following.

@TestPropertySource(properties ="spring.autoconfigure.exclude=org.springframework.cloud.stream.test.binder.TestSupportBinderAutoConfiguration")

Our case removing the spring-cloud-stream-test-support library solved the problem.