My unit tests with Mockito throws the following error:

Mockito cannot mock this class: class android.car.Car.

If you’re not sure why you’re getting this error, please open an issue on GitHub.

Java : 17
JVM vendor name : JetBrains s.r.o.
JVM vendor version : 17.0.10+0-17.0.10b1087.21-11609105
JVM name : OpenJDK 64-Bit Server VM
JVM version : 17.0.10+0-17.0.10b1087.21-11609105
JVM info : mixed mode
OS name : Linux
OS version : 6.8.0-49-generic

You are seeing this disclaimer because Mockito is configured to create inlined mocks.
You can learn about inline mocks and their limitations under item #39 of the Mockito class javadoc.

Underlying exception : org.mockito.exceptions.base.MockitoException: Cannot instrument class android.car.Car because it or one of its supertypes could not be initialized
org.mockito.exceptions.base.MockitoException:
Mockito cannot mock this class: class android.car.Car.

If you're not sure why you're getting this error, please open an issue on GitHub.

Java : 17
JVM vendor name : JetBrains s.r.o.
JVM vendor version : 17.0.10+0-17.0.10b1087.21-11609105
JVM name : OpenJDK 64-Bit Server VM
JVM version : 17.0.10+0-17.0.10b1087.21-11609105
JVM info : mixed mode
OS name : Linux
OS version : 6.8.0-49-generic

You are seeing this disclaimer because Mockito is configured to create inlined mocks.
You can learn about inline mocks and their limitations under item #39 of the Mockito class javadoc.

    Underlying exception : org.mockito.exceptions.base.MockitoException: Cannot instrument class android.car.Car because it or one of its supertypes could not be initialized
    at BaseViewModelTests.setup(BaseViewModelTests.kt:26)
    at [email protected]/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at [email protected]/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
    at [email protected]/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at [email protected]/java.lang.reflect.Method.invoke(Method.java:568)
    at app//org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
    at app//org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at app//org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
    at app//org.junit.internal.runners.statements.RunBefores.invokeMethod(RunBefores.java:33)
    at app//org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
    at app//org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at app//org.robolectric.RobolectricTestRunner$HelperTestRunner$1.evaluate(RobolectricTestRunner.java:489)
    at app//org.robolectric.internal.SandboxTestRunner$2.lambda$evaluate$2(SandboxTestRunner.java:291)
    at app//org.robolectric.internal.bytecode.Sandbox.lambda$runOnMainThread$0(Sandbox.java:104)
    at [email protected]/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at [email protected]/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
    at [email protected]/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
    at [email protected]/java.lang.Thread.run(Thread.java:840)
    Caused by: org.mockito.exceptions.base.MockitoException: Cannot instrument class android.car.Car because it or one of its supertypes could not be initialized
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:168)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:399)
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:190)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:410)
    ... 18 more
    Caused by: java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at org.robolectric.internal.bytecode.ShadowWrangler.classInitializing(ShadowWrangler.java:164)
    at org.robolectric.internal.bytecode.RobolectricInternals.classInitializing(RobolectricInternals.java:21)
    at android.car.Car.(Car.java)
    at java.base/java.lang.Class.forName0(Native Method)
    at java.base/java.lang.Class.forName(Class.java:467)
    at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.assureInitialization(InlineBytecodeGenerator.java:236)
    at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.triggerRetransformation(InlineBytecodeGenerator.java:261)
    at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.mockClass(InlineBytecodeGenerator.java:218)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.lambda$mockClass$0(TypeCachingBytecodeGenerator.java:78)
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:168)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:399)
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:190)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:410)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.mockClass(TypeCachingBytecodeGenerator.java:75)
    at org.mockito.internal.creation.bytebuddy.InlineDelegateByteBuddyMockMaker.createMockType(InlineDelegateByteBuddyMockMaker.java:427)
    at org.mockito.internal.creation.bytebuddy.InlineDelegateByteBuddyMockMaker.doCreateMock(InlineDelegateByteBuddyMockMaker.java:386)
    at org.mockito.internal.creation.bytebuddy.InlineDelegateByteBuddyMockMaker.createMock(InlineDelegateByteBuddyMockMaker.java:365)
    at org.mockito.internal.creation.bytebuddy.InlineByteBuddyMockMaker.createMock(InlineByteBuddyMockMaker.java:56)
    at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:99)
    at org.mockito.internal.MockitoCore.mock(MockitoCore.java:84)
    at org.mockito.Mockito.mock(Mockito.java:2162)
    at org.mockito.Mockito.mock(Mockito.java:2077)
    ... 18 more
    Caused by: java.lang.reflect.InvocationTargetException
    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.robolectric.internal.bytecode.RobolectricInternals.performStaticInitialization(RobolectricInternals.java:53)
    at org.robolectric.internal.bytecode.ShadowWrangler.classInitializing(ShadowWrangler.java:161)
    ... 39 more
    Caused by: java.lang.IllegalArgumentException: key.length > 31
    at android.os.SystemProperties.getInt(SystemProperties.java:77)
    at android.car.Car.staticInitializer(Car.java:141)
    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 org.robolectric.internal.bytecode.RobolectricInternals.performStaticInitialization(RobolectricInternals.java:53)
    at org.robolectric.internal.bytecode.ShadowWrangler.classInitializing(ShadowWrangler.java:161)
    at org.robolectric.internal.bytecode.RobolectricInternals.classInitializing(RobolectricInternals.java:21)
    at android.car.Car.(Car.java)
    at java.base/java.lang.Class.forName0(Native Method)
    at java.base/java.lang.Class.forName(Class.java:467)
    at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.assureInitialization(InlineBytecodeGenerator.java:236)
    at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.triggerRetransformation(InlineBytecodeGenerator.java:261)
    at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.mockClass(InlineBytecodeGenerator.java:218)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.lambda$mockClass$0(TypeCachingBytecodeGenerator.java:78)
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:168)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:399)
    at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:190)
    at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:410)
    at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.mockClass(TypeCachingBytecodeGenerator.java:75)
    at org.mockito.internal.creation.bytebuddy.InlineDelegateByteBuddyMockMaker.createMockType(InlineDelegateByteBuddyMockMaker.java:427)
    at org.mockito.internal.creation.bytebuddy.InlineDelegateByteBuddyMockMaker.doCreateMock(InlineDelegateByteBuddyMockMaker.java:386)
    at org.mockito.internal.creation.bytebuddy.InlineDelegateByteBuddyMockMaker.createMock(InlineDelegateByteBuddyMockMaker.java:365)
    at org.mockito.internal.creation.bytebuddy.InlineByteBuddyMockMaker.createMock(InlineByteBuddyMockMaker.java:56)
    at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:99)
    at org.mockito.internal.MockitoCore.mock(MockitoCore.java:84)
    at org.mockito.Mockito.mock(Mockito.java:2162)
    at org.mockito.Mockito.mock(Mockito.java:2077)
    at BaseViewModelTests.setup(BaseViewModelTests.kt:26)
    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)
    ... 13 more

The line triggering this error is really basic –

val mockCar = Mockito.mock(Car::class.java)

The build.gradle test dependencies for my project looks like this –

testImplementation "junit:junit:4.13.2"
testImplementation "org.mockito:mockito-co6re:5.14.1"
testImplementation "org.mockito.kotlin:mockito-kotlin:5.4.0"
testImplementation 'org.robolectric:robolectric:4.13'

I also checked Car.java-

public final class Car {
private static final String PROPERTY_PLATFORM_MINOR_VERSION = “ro.android.car.version.platform_minor”;
….

But it did not extend from any other class. It is final class, but will that cause an issue for Mocking? Any ideas what could be the reason for this error?

Also, i raised a GitHub bug for this issue 2 days ago, but did not get any response so far –
https://github.com/mockito/mockito/issues/3550

Any help is highly appreciated. Thanks! 🙂