Mockito cannot mock JdbcTemplate - junit

Question

I'm currently working on setting up JUnit tests using Mockito. As of right now, I'm unable to get a very basic test to run:
#ExtendWith(MockitoExtension.class)
public class TestDAO {
private final Logger logger = LoggerFactory.getLogger(TestDAO.class.getName());
#Mock
public JdbcTemplate jdbcTemplate = new JdbcTemplate();
#InjectMocks
private TestDAOImpl dao;
#Rule
public MockitoRule mockitoRule = MockitoJUnit.rule();
#BeforeEach
public void init() {
System.out.println("Hello init");
}
#Test
public void getAllEntries() {
System.out.println("hello world");
}
}
For the moment, all I want is to see if it can print out hello world. Every time I run the test, though, I receive an error that:
Underlying exception : java.lang.IllegalArgumentException: object is not an instance of declaring class
Which seems to point to the JdbcTemplate as the culprit. I'm trying to mock that database connection so I can mock CRUD operations later.
This is my first time using Mockito, so any help would be appreciated. The full stack trace is below:
org.mockito.exceptions.base.MockitoException:
Mockito cannot mock this class: class org.springframework.jdbc.core.JdbcTemplate.
Mockito can only mock non-private & non-final classes.
If you're not sure why you're getting this error, please report to the mailing list.
Java : 1.8
JVM vendor name : Oracle Corporation
JVM vendor version : 25.5-b02
JVM name : Java HotSpot(TM) Client VM
JVM version : 1.8.0_05-b13
JVM info : mixed mode
OS name : Windows 7
OS version : 6.1
Underlying exception : java.lang.IllegalArgumentException: object is not an instance of declaring class
at org.mockito.junit.jupiter.MockitoExtension.beforeEach(MockitoExtension.java:165)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeBeforeEachCallbacks$0(TestMethodTestDescriptor.java:129)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor$$Lambda$192/20816428.execute(Unknown Source)
at org.junit.jupiter.engine.execution.ThrowableCollector.execute(ThrowableCollector.java:40)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeBeforeMethodsOrCallbacksUntilExceptionOccurs(TestMethodTestDescriptor.java:155)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeBeforeEachCallbacks(TestMethodTestDescriptor.java:128)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:107)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:58)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$3(HierarchicalTestExecutor.java:113)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor$$Lambda$142/16902902.execute(Unknown Source)
at org.junit.platform.engine.support.hierarchical.SingleTestExecutor.executeSafely(SingleTestExecutor.java:66)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.executeRecursively(HierarchicalTestExecutor.java:108)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.execute(HierarchicalTestExecutor.java:79)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$2(HierarchicalTestExecutor.java:121)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor$$Lambda$145/18524506.accept(Unknown Source)
at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175)
at java.util.Iterator.forEachRemaining(Iterator.java:116)
at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:512)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:502)
at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$3(HierarchicalTestExecutor.java:121)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor$$Lambda$142/16902902.execute(Unknown Source)
at org.junit.platform.engine.support.hierarchical.SingleTestExecutor.executeSafely(SingleTestExecutor.java:66)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.executeRecursively(HierarchicalTestExecutor.java:108)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.execute(HierarchicalTestExecutor.java:79)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$2(HierarchicalTestExecutor.java:121)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor$$Lambda$145/18524506.accept(Unknown Source)
at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175)
at java.util.Iterator.forEachRemaining(Iterator.java:116)
at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:512)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:502)
at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.lambda$executeRecursively$3(HierarchicalTestExecutor.java:121)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor$$Lambda$142/16902902.execute(Unknown Source)
at org.junit.platform.engine.support.hierarchical.SingleTestExecutor.executeSafely(SingleTestExecutor.java:66)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.executeRecursively(HierarchicalTestExecutor.java:108)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor$NodeExecutor.execute(HierarchicalTestExecutor.java:79)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:55)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:43)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:170)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:154)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:90)
at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:74)
at com.intellij.rt.execution.junit.IdeaTestRunner$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)
Suppressed: java.lang.NullPointerException
at org.mockito.junit.jupiter.MockitoExtension.afterEach(MockitoExtension.java:211)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeAfterEachCallbacks$11(TestMethodTestDescriptor.java:217)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor$$Lambda$196/31005110.execute(Unknown Source)
at org.junit.jupiter.engine.execution.ThrowableCollector.execute(ThrowableCollector.java:40)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeAllAfterMethodsOrCallbacks$13(TestMethodTestDescriptor.java:229)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor$$Lambda$195/6646756.accept(Unknown Source)
at java.util.ArrayList.forEach(ArrayList.java:1234)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeAllAfterMethodsOrCallbacks(TestMethodTestDescriptor.java:227)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeAfterEachCallbacks(TestMethodTestDescriptor.java:216)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:119)
... 49 more
Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at net.bytebuddy.description.type.TypeDescription$Generic$AnnotationReader$ForTypeArgument.resolve(TypeDescription.java:3083)
at net.bytebuddy.description.type.TypeDescription$Generic$AnnotationReader$Delegator$Chained.resolve(TypeDescription.java:2868)
at net.bytebuddy.description.type.TypeDescription$Generic$AnnotationReader$ForTypeArgument.resolve(TypeDescription.java:3056)
at net.bytebuddy.description.type.TypeDescription$Generic$AnnotationReader$Delegator.asList(TypeDescription.java:2822)
at net.bytebuddy.description.type.TypeDescription$Generic$OfTypeVariable$ForLoadedType.getDeclaredAnnotations(TypeDescription.java:5130)
at net.bytebuddy.description.type.TypeDescription$Generic$OfTypeVariable$Symbolic.getDeclaredAnnotations(TypeDescription.java:4941)
at net.bytebuddy.description.type.TypeDescription$Generic$OfTypeVariable$WithAnnotationOverlay.getDeclaredAnnotations(TypeDescription.java:5204)
at net.bytebuddy.implementation.attribute.AnnotationAppender$ForTypeAnnotations.apply(AnnotationAppender.java:639)
at net.bytebuddy.implementation.attribute.AnnotationAppender$ForTypeAnnotations.onTypeVariable(AnnotationAppender.java:611)
at net.bytebuddy.implementation.attribute.AnnotationAppender$ForTypeAnnotations.onTypeVariable(AnnotationAppender.java:333)
at net.bytebuddy.description.type.TypeDescription$Generic$OfTypeVariable.accept(TypeDescription.java:4852)
at net.bytebuddy.implementation.attribute.AnnotationAppender$ForTypeAnnotations.onParameterizedType(AnnotationAppender.java:601)
at net.bytebuddy.implementation.attribute.AnnotationAppender$ForTypeAnnotations.onParameterizedType(AnnotationAppender.java:333)
at net.bytebuddy.description.type.TypeDescription$Generic$OfParameterizedType.accept(TypeDescription.java:4372)
at net.bytebuddy.implementation.attribute.MethodAttributeAppender$ForInstrumentedMethod.apply(MethodAttributeAppender.java:183)
at net.bytebuddy.implementation.attribute.MethodAttributeAppender$Compound.apply(MethodAttributeAppender.java:425)
at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod$WithBody.applyAttributes(TypeWriter.java:617)
at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod$WithBody.applyBody(TypeWriter.java:609)
at net.bytebuddy.dynamic.scaffold.TypeWriter$MethodPool$Record$ForDefinedMethod.apply(TypeWriter.java:528)
at net.bytebuddy.dynamic.scaffold.TypeWriter$Default$ForCreation.create(TypeWriter.java:4167)
at net.bytebuddy.dynamic.scaffold.TypeWriter$Default.make(TypeWriter.java:1653)
at net.bytebuddy.dynamic.scaffold.subclass.SubclassDynamicTypeBuilder.make(SubclassDynamicTypeBuilder.java:183)
at net.bytebuddy.dynamic.scaffold.subclass.SubclassDynamicTypeBuilder.make(SubclassDynamicTypeBuilder.java:163)
at net.bytebuddy.dynamic.DynamicType$Builder$AbstractBase.make(DynamicType.java:2669)
at net.bytebuddy.dynamic.DynamicType$Builder$AbstractBase$Delegator.make(DynamicType.java:2771)
at org.mockito.internal.creation.bytebuddy.SubclassBytecodeGenerator.mockClass(SubclassBytecodeGenerator.java:128)
at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator$1.call(TypeCachingBytecodeGenerator.java:37)
at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator$1.call(TypeCachingBytecodeGenerator.java:34)
at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:137)
at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:344)
at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:159)
at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:353)
at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.mockClass(TypeCachingBytecodeGenerator.java:32)
at org.mockito.internal.creation.bytebuddy.SubclassByteBuddyMockMaker.createMockType(SubclassByteBuddyMockMaker.java:71)
at org.mockito.internal.creation.bytebuddy.SubclassByteBuddyMockMaker.createMock(SubclassByteBuddyMockMaker.java:42)
at org.mockito.internal.creation.bytebuddy.ByteBuddyMockMaker.createMock(ByteBuddyMockMaker.java:25)
at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:35)
at org.mockito.internal.MockitoCore.mock(MockitoCore.java:69)
at org.mockito.Mockito.mock(Mockito.java:1895)
at org.mockito.internal.configuration.MockAnnotationProcessor.processAnnotationForMock(MockAnnotationProcessor.java:41)
at org.mockito.internal.configuration.MockAnnotationProcessor.process(MockAnnotationProcessor.java:19)
at org.mockito.internal.configuration.MockAnnotationProcessor.process(MockAnnotationProcessor.java:16)
at org.mockito.internal.configuration.IndependentAnnotationEngine.createMockFor(IndependentAnnotationEngine.java:38)
at org.mockito.internal.configuration.IndependentAnnotationEngine.process(IndependentAnnotationEngine.java:62)
at org.mockito.internal.configuration.InjectingAnnotationEngine.processIndependentAnnotations(InjectingAnnotationEngine.java:57)
at org.mockito.internal.configuration.InjectingAnnotationEngine.process(InjectingAnnotationEngine.java:41)
at org.mockito.MockitoAnnotations.initMocks(MockitoAnnotations.java:69)
at org.mockito.internal.framework.DefaultMockitoSession.<init>(DefaultMockitoSession.java:36)
at org.mockito.internal.session.DefaultMockitoSessionBuilder.startMocking(DefaultMockitoSessionBuilder.java:78)
... 56 more

Answer 1

Please recheck your imports and don't mix JUnit 4 and JUnit 5, it may be the source of your problem.
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;
import org.springframework.jdbc.core.JdbcTemplate;
#ExtendWith ( MockitoExtension.class )
public class SampleTest {
#Mock
private JdbcTemplate jdbcTemplate = new JdbcTemplate();
#InjectMocks
private TestObject testObject;
#BeforeEach
public void init() {
System.out.println( "Hello init" );
}
#Test
public void getAllEntries() {
System.out.println( "hello world" );
}
}
It is working perfectly with my example. Be careful with #Test annotation - it has to be JUnit 5 annotation, moreover #Rule annotation doesn't exist in JUnit 5.
If it won't help, please show us your dependencies with versions.