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org.mockito.exceptions.misusing.InjectMocksException: Cannot instantiate #InjectMocks

I am using #InjectMocks to inject Repository Implementation into my Test class, but it throws InjectMocksException. Below is my code and Error, please help how to resolve this error?
Error:
org.mockito.exceptions.misusing.InjectMocksException:
Cannot instantiate #InjectMocks field named 'muRepository' of type 'class com.example.MyrRepositoryImpl'.
You haven't provided the instance at field declaration so I tried to construct the instance.
However the constructor or the initialization block threw an exception : null
at org.mockito.internal.runners.DefaultInternalRunner$1$1.evaluate(DefaultInternalRunner.java:44)
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.mockito.internal.runners.DefaultInternalRunner$1.run(DefaultInternalRunner.java:77)
at org.mockito.internal.runners.DefaultInternalRunner.run(DefaultInternalRunner.java:83)
at org.mockito.internal.runners.StrictRunner.run(StrictRunner.java:39)
at org.mockito.junit.MockitoJUnitRunner.run(MockitoJUnitRunner.java:163)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)
Caused by: java.lang.NullPointerException
at com.example.MyRepositoryImpl.<init>(MyRepositoryImpl.java:27)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
Injecting:
#InjectMocks
private MyRepositoryImpl myRepository;
Test:
#Test (expected = NullPointerException.class )
public void procTest( ) throws Exception
{
when( addProc.execute( null,
null,
null
)
).thenThrow( new NullPointerException() );
myRepository.addUser( null );
}
Repository:
public class MyRepositoryImpl implements MyRepository
{
private final AddProc addProc;
#Autowired
public MyRepositoryImpl( final ProcFactory procFactory )
{
this.addProc = procFactory.create( AddProc.class ); //this is line 27 referenced in error
}
#Override
public User addUser( User user)
{
return addProc.execute(
user.getUserName( ),
user.getFirstName( ),
user.getLastName( )
);
}
}

Mockito uses the constroctor injection but you didnt use mock object for ProcFactory class.
So null pointer exception occurs. Either you have to use ProcFactory as mock in test class or, you have to add null check.
#Mock
private ProcFactory procFactory;
Regards

Having seen that you are running tests on JUnit 4, in order to initialize and inject mocks through #InjectMocks needs to use #RunWith(MockitoJUnitRunner.class) as test runner or Mockito.initMocks(this) in the setup step.
#Before
public void setUp() {
MockitoAnnotations.initMocks(this);
}

Junit : How to cover CompletableFuture Code

I am new to Junit and come across this problem recently. I am not able code write test cases wherever I used CompletableFuture in my code. Like below Java file
Updated
AuditService.java
#Autowired
Executor existingThreadPool;
#Override
public void auditData(List<ErrorDetails> alertList) {
CompletableFuture.runAsync(() -> {
if (alertList.isEmpty())
//privateMethodCall1
else
//privateMethodCall2
}, existingThreadPool);
}
I followed this link and tried below solution still getting NPE for CompletableFuture Like below error.
AuditServiceTest.java
#InjectMock
AuditService auditService;
#Mock
private CompletableFuture<Void> completableFuture = null;
#Before
public void setup() {
MockitoAnnotations.initMocks(this);
completableFuture = CompletableFuture.runAsync(new Runnable() {
#Override
public void run() {}
},Executors.newSingleThreadExecutor());
}
#Test
public void shouldAuditData() {
List<ErrorDetails> alertList = new ArrayList();
auditService.auditData(alertList);
}
ERROR
java.lang.NullPointerException
at java.util.concurrent.CompletableFuture.screenExecutor(CompletableFuture.java:415)
at java.util.concurrent.CompletableFuture.runAsync(CompletableFuture.java:1858)
at com.service.impl.AuditService.auditData(AuditService.java:15)
at com.service.impl.AuditServiceTest.shouldAuditData(AuditServiceTest.java:249)
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.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
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.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

You need to test your logic and you don't need to mock the static method CompletableFuture.runAsync(...). So your test should look like normal test with exception that you need to wait some time to be sure that asynchronous code is executed, because it is not executed in the same thread. So for the moment I will give you example that you can use with Thread.sleep() which is not good convention, in additional question you can ask how to avoid usages of Thread.sleep().
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.junit.MockitoJUnitRunner;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
#RunWith(MockitoJUnitRunner.class)
public class AuditServiceTest {
#Mock
Service serviceMock;
#Test
public void shouldAuditData() {
AuditService auditService = new AuditService(serviceMock);
List<Object> alertList = new ArrayList();
auditService.auditData(alertList);
// you can wait with Thread.sleep()
// because the execution is asynchronous
Mockito.verify(serviceMock).method1();
Mockito.verify(serviceMock, Mockito.never()).method2();
}
}
class AuditService {
Executor existingThreadPool = Executors.newSingleThreadExecutor();
Service service;
public AuditService(Service service) {
this.service = service;
}
public void auditData(List<Object> alertList) {
CompletableFuture.runAsync(() -> {
if (alertList.isEmpty()) {
service.method1();
} else {
service.method2();
}
}, existingThreadPool);
}
}
class Service {
public void method1(){};
public void method2(){};
}

in AuditService class , Executor is autowired. that is perfect setup for unit tests. what you have to do is , come up with separate configuration for test and Executor implementation should be a inline executor (you can provide your own implementation which calls runnable.run in the same calling thread).
To do this you can use some implementations provided spring-test.
ex: AbstractJUnit4SpringContextTests
if you dont like to go with spring-test support, now you have injected mock Executor to AuditService. so you can mock the execute method with providing custom stub.Answer and execute the runnable.run.
Mockito.doAnswer(new Answer() {
public Object answer(InvocationOnMock invocation) {
Object[] args = invocation.getArguments();
((Runnable)args[0]).run();
return null; // void method, so return null
}
}).when(executor).execute(Mockito.any(Runnable.class));

Mockito Spy doReturn calls original method

I am new to Mockito. I am aware that spy object will never call original method for doReturn, But in my code, which is not happening
import static org.junit.Assert.assertTrue;
import static org.mockito.Matchers.any;
import static org.mockito.Mockito.spy;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.mockito.runners.MockitoJUnitRunner;
class MyClass {
public int method1(){
int x =10;
x = method2(2);
return x;
}
public int method2(int y){
method3();
return 20;
}
public int method3(){
return 30;
}
}
#RunWith(MockitoJUnitRunner.class)
public class Method1Test {
private MyClass myClass = new MyClass();
#Before
public void setup(){}
#Test
public void test01(){
MyClass spyMyClass = spy(myClass);
doReturn(28).when(spyMyClass).method2(any());
int a = spyMyClass.method1();
assertTrue("We did it!!!",a==20);
}
}
Below is the error stacktrace:
java.lang.NullPointerException
at com.Method1Test.test01(Method1Test.java:45)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
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.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
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.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37)
at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
org.mockito.exceptions.misusing.InvalidUseOfMatchersException:
Misplaced argument matcher detected here:
-> at com.Method1Test.test01(Method1Test.java:45)
Please someone help me out on above and also provide me fix for above issue.

The issue is caused by a type mismatch on the parameter being passed to method2. That's what this part of the exception message is telling you:
org.mockito.exceptions.misusing.InvalidUseOfMatchersException:
Misplaced argument matcher detected here:
The following test passes:
#Test
public void test01(){
MyClass spyMyClass = spy(myClass);
doReturn(28).when(spyMyClass).method2(anyInt());
int a = spyMyClass.method1();
assertTrue("We did it!!!",a==28);
}
There are two changes here:
Use anyInt() instead of any()
Assert that a==28 because you are telling the stub to return 28

Nullpointer exception on constructor injection and works with field injection mockito

I have an abstract class which has a dependency which is being autowired:
public abstract class ClassB {
#Autowired
private ClassC classC;
public String getValue() {
classC.getSomeMethod();
}
}
I've a class which extends this abstract class:
#Component
public class ClassA extends ClassB {
#Autowired
private ClassD classD;
public String getClassAMethod() {
String value = getValue();
String dReturn = classD.getD();
return value + dReturn;
}
}
Now while doing UnitTesting I can do:
public class ClassATest {
#Mock
private ClassC classC;
#Mock
private ClassD classD;
#InjectMocks
private ClassA classA;
#Test
public void testSomething() {
when(classC.getSometMethod()).thenReturn("classC");
when(classD.getD()).thenReturn("classD");
assertEquals(classA.getClassAMethod(), "classCclassD");
}
}
This works fine, however if I use constructor injection for ClassA I get a Null pointer exception for classC.
#Component
#RequiredArgsConstructor(onConstructor = #__(#Autowired))
public class ClassA extends ClassB {
private final ClassD classD;
public String getClassAMethod() {
String value = getValue();
String dReturn = classD.getD();
return value + dReturn;
}
}
In the second case I even tried replacing InjectMocks with a normal constructor invocation, but ClassC object doesn't get mocked.
Stack trace:
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.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
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.mockito.internal.runners.DefaultInternalRunner$1.run(Unknown Source)
at org.mockito.internal.runners.DefaultInternalRunner.run(Unknown Source)
at org.mockito.internal.runners.StrictRunner.run(Unknown Source)
at org.mockito.junit.MockitoJUnitRunner.run(Unknown Source)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$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)

Lombok's #AllArgsConstructor and #RequiredArgsConstructor only cover fields that are declared in the class itself. Fields from superclasses are not considered, as lombok cannot access those classes, because they are not yet resolved at the time lombok runs during the compilation process.
As a result in your case, the constructor that is generated for ClassA only has ClassD classD as argument, but not ClassC classC. (You can see that in the class outline view of your IDE, or by delomboking your code.) Therefore, classC remains uninitialized, causing the NPE.
So lombok cannot help you in your case, unfortunately. You have to write your constructor manually.

Spring Retry #Retryable not retrying nor recovering

When I run my unit test I would expect the method thisFails() to retry 3 times and then I would expect to see the recovery logger line printed, but it only tries once and then throws the exception. The output at the bottom is after I run my test.
What am I missing?
Feel free to ignore this section, and jump down to the code. The linter did not think I had sufficient exposition in order to post. I thought that was sufficiently worded to get my question across but for some reason I am not allowed to post this question unless I write more stuff. So here is more stuff, blah blah.
--Spring Boot Application--
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.retry.annotation.EnableRetry;
#EnableRetry
#SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
--Service--
package com.example.demo;
import lombok.extern.slf4j.Slf4j;
import org.springframework.retry.annotation.Recover;
import org.springframework.retry.annotation.Retryable;
import org.springframework.stereotype.Service;
#Service
#Slf4j
public class MyService {
#Retryable(include = RuntimeException.class)
public int thisFails() {
log.info("Help I am failing");
throw new RuntimeException();
}
#Recover
public int thisRecovers(RuntimeException re) {
log.info("I recovered");
return 0;
}
}
--Test Class--
package com.example.demo;
import static org.junit.Assert.*;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.runners.MockitoJUnitRunner;
#RunWith(MockitoJUnitRunner.class)
public class MyServiceTest {
#InjectMocks
MyService service;
#Test
public void recovery(){
service.thisFails();
}
}
Output
Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/bin/java (0x10983b4c0) and /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/jre/lib/libinstrument.dylib (0x1099034e0). One of the two will be used. Which one is undefined.
12:58:32.067 [main] INFO com.example.demo.MyService - Help I am failing
java.lang.RuntimeException
at com.example.demo.MyService.thisFails(MyService.java:15)
at com.example.demo.MyServiceTest.recovery(MyServiceTest.java:17)
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.InvokeMethod.evaluate(InvokeMethod.java:17)
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$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37)
at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$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)
Process finished with exit code 255

Spring Retry requires a Spring ApplicationContext; you are using Mockito's #InjectMocks instead of Spring's #Autowired, together with the SpringJunit4ClassRunner (or the newer SpringRUnner) #RunWith.
Since there's no ApplicationContext for the test, there's no retry.