What causes java.lang.IllegalStateException: Failed to load ApplicationContext error?-CodePudding

I am new to spring boot, so I don't understand what caused the error mentioned above here since everything gives no warnings and is imported from official libraries

import org.junit.jupiter.api.Assertions
import org.junit.jupiter.api.Test
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest
import org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager

import javax.sql.DataSource


@DataJpaTest
class RepositoryTest{
    @Autowired
    lateinit var entityManager: TestEntityManager

    @Autowired
    lateinit var dataSource: DataSource

    @Test
    fun `context loads`(){
        Assertions.assertNotNull(entityManager)
        Assertions.assertNotNull(dataSource)
    }
}

Stack trace:

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.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:118)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
    at org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener.prepareTestInstance(SpringBootDependencyInjectionTestExecutionListener.java:43)
    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:197)
    at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179)
    at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
    at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:310)
    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:735)
    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734)
    at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762)
    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$4(ClassBasedTestDescriptor.java:272)
    at java.base/java.util.Optional.orElseGet(Optional.java:364)
    at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$testInstancesProvider$5(ClassBasedTestDescriptor.java:271)
    at org.junit.jupiter.engine.execution.TestInstancesProvider.getTestInstances(TestInstancesProvider.java:31)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$prepare$0(TestMethodTestDescriptor.java:102)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:101)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:66)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$prepare$2(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.prepare(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:90)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$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$9(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$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$9(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)
    at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)
    at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53)
    at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:71)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
    at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'flyway' defined in class path resource [org/springframework/boot/autoconfigure/flyway/FlywayAutoConfiguration$FlywayConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.flywaydb.core.Flyway]: Factory method 'flyway' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource': Invocation of init method failed; nested exception is java.lang.IllegalStateException: Failed to replace DataSource with an embedded database for tests. If you want an embedded database please put a supported one on the classpath or tune the replace attribute of @AutoConfigureTestDatabase.
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:638)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1352)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1195)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:582)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:908)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:730)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:302)
    at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:120)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)
    ... 72 more
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.flywaydb.core.Flyway]: Factory method 'flyway' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource': Invocation of init method failed; nested exception is java.lang.IllegalStateException: Failed to replace DataSource with an embedded database for tests. If you want an embedded database please put a supported one on the classpath or tune the replace attribute of @AutoConfigureTestDatabase.
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653)
    ... 92 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource': Invocation of init method failed; nested exception is java.lang.IllegalStateException: Failed to replace DataSource with an embedded database for tests. If you want an embedded database please put a supported one on the classpath or tune the replace attribute of @AutoConfigureTestDatabase.
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1804)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1380)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory$DependencyObjectProvider.getIfUnique(DefaultListableBeanFactory.java:2063)
    at org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration$FlywayConfiguration.flyway(FlywayAutoConfiguration.java:117)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:568)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
    ... 93 more
Caused by: java.lang.IllegalStateException: Failed to replace DataSource with an embedded database for tests. If you want an embedded database please put a supported one on the classpath or tune the replace attribute of @AutoConfigureTestDatabase.
    at org.springframework.util.Assert.state(Assert.java:76)
    at org.springframework.boot.test.autoconfigure.jdbc.TestDatabaseAutoConfiguration$EmbeddedDataSourceFactory.getEmbeddedDatabase(TestDatabaseAutoConfiguration.java:192)
    at org.springframework.boot.test.autoconfigure.jdbc.TestDatabaseAutoConfiguration$EmbeddedDataSourceFactoryBean.afterPropertiesSet(TestDatabaseAutoConfiguration.java:151)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1863)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800)
    ... 108 more

CodePudding user response：

It may be worth explaining a bit about how to read error messages with stack traces, as many people seem to struggle with it.

When the JVM hits a problem it can't handle (whether from Kotlin code, or Java, or anything else it runs), it throws an Exception, Error, or other Throwable. That usually prints out a lot of info which gets shown on the console and/or in the logs. It can be intimidating, but it's really helpful in finding out what went wrong and how to fix it. (That's why it's usually a good idea to include it all when posting questions to places like StackOverflow.)

A stack trace shows exactly what code was running at the point when the problem happened. It's in reverse order: the top row has the exact line where it happened; below that is the method which called that one, then the one which called that, and so on up to the top level.

Each line gives the fully-qualified name of the method that was running, and the class it's in. (This is the JVM's internal name, so the names of inner classes and anonymous classes are separated from their containing class with a $.) If available, it also gives the filename and line number of the source code from which it was compiled.

So the most interesting line of a stack trace is usually the top one, as that shows where the problem occurred. Of course, that might not be where the underlying bug is — especially when the top line is in a library or framework, as it is here. So you may need to search down the stack trace (i.e. up the call stack) to find your code, and then go from there.

However, exceptions don't always stand alone — one exception can cause another, and so on. When printing an exception, its stack trace, will be followed its cause, and then the cause of that, right back to the original exception. These are indicated by the prefix Caused by:.

Usually, it's the original exception you want to see. So this the usual way to read a big JVM error with stack trace(s):

Scan down to find the last exception message. This will start with Caused by: if it's not at the top.
Read that line carefully. It will have the classname of the exception or error, and usually a message giving details. This may tell you all you need to know. If not:
Look at the next line, which shows you exactly where in the code this exception/error was thrown.
If that's in a library or framework, scan down until you find a line referring to your own code.
If you don't find such a line, go back to the previous exception message, and repeat.
If you do find your own code, look at your source code and see if you can figure out what happened. (If you don't, then the error can be harder to track down; the library/framework methods listed may give you some clues.)

In this case, the last exception is:

Caused by: java.lang.IllegalStateException: Failed to replace DataSource with an embedded database for tests. If you want an embedded database please put a supported one on the classpath or tune the replace attribute of @AutoConfigureTestDatabase.

That tells you the real problem here. (So you don't even need to look at the stack trace below. Which is good, because Spring initialisation problems usually happen when none of your code is actually running, so the stack traces are less helpful.)

I don't have a full answer for what to do about it, though I think you'll need to configure a test database for it to use. I've had good results with an H2 in-memory database, so you might want to look at that. A quick search finds several existing questions about it, so you should be able to find what you need to know.