Autowiring returns a NullPointerException - java

I have an interface RestService and a RestServiceImpl class shown below:
//RestService:
public interface RestService {
public void printMessage();
}
//RestServiceImpl:
#Service
public class RestServiceImpl implements RestService {
public RestServiceImpl() {
}
public void printMessage() {
System.out.println("This is a test message.");
}
}
When testing the printMessage() method, I get a NullPointerException. I'm pretty sure I autowired everything correctly and have added the appropriate annotations to the classes. Not sure why this is happening.
#SpringBootTest
public class RestServiceTest {
#Autowired
RestService restService;
#Test
public void someTest() {
restService.printMessage(); //Thows NullPointerException
}
}
What am I missing here?

First of all, make sure the whole spring infrastructure is plugged in, a "bridge" between the JUnit framework and spring:
There is no #RunWith(SpringRunner.class) on the test:
#RunWith(SpringRunner.class)
#SpringBootTest
public class RestServiceTest {
#Autowired
RestService restService;
#Test
public void someTest() {
restService.printMessage(); //Thows NullPointerException
}
}

Add #RunWith(SpringRunner.class) at top of RestServiceTest.

Related

Spring ProxyFactoryBean #Autowired not working

I need to intercept methods from a interface, and found this implementation of MethodInterceptor, which I tested on a new spring app and worked.
The problem is, I can't seem to get it working on the spring application I need it to.
#Configuration
public class TestMethodConfig {
#Autowired
private TestService testService;
#Bean
#Primary
public ProxyFactoryBean testProxyFactoryBean() {
ProxyFactoryBean testProxyFactoryBean = new ProxyFactoryBean();
testProxyFactoryBean.setTarget(testService);
testProxyFactoryBean.setInterceptorNames("testMethodInterceptor");
return testProxyFactoryBean;
}
}
#Service
public class TestServiceImpl implements TestService{
#Override
public void testMethod(String test) {
System.out.println("testService String");
}
}
public interface TestService{
void testMethod(String test);
}
#RestController
public class Controller {
#Autowired
private TestService testProxyFactoryBean;
#GetMapping(value = "/test")
public void test(){
testProxyFactoryBean.testMethod("valor");
}
}
#Component
public class TestMethodInterceptor implements MethodInterceptor {
#Override
public Object invoke(MethodInvocation invocation) throws Throwable {
System.out.println("before method");
System.out.println("invocation: " + Arrays.toString(invocation.getArguments()));
Object retVal = invocation.proceed();
System.out.println("after method");
return retVal;
}
}
I used Spring Actuator to check the beans relations, and I found that the #Autowired TestService on Controller should be getting assigned to testProxyFactoryBean, but its getting assigned to the TestServiceImpl bean instead, so I believe there is a problem creating the proxy.
In short
I don't know how/why it was:
on a new spring app and worked.
but:
I can't seem to get it working on the spring application I need it to.
..can probably be fixed!
Make it consistent
Or:
#Configuration
public class TestMethodConfig {
#Autowired
private TestService testService;
}
...
// !!
public class TestServiceImpl implements TestService{
#Override
public void testMethod(String test) {
System.out.println("testService String");
}
}
...
#Service // !!!
public interface TestService{
void testMethod(String test);
}
...
#RestController
public class Controller {
#Autowired
private TestService testProxyFactoryBean;
...
Or: Impl!
(Use Interface and Impl consistently!)
In Detail
6.4. Using the ProxyFactoryBean to Create AOP Proxies
esp. Proxying Interfaces.
So with "least impact" (and java config), it should be:
#Configuration
public class TestMethodConfig {
// !!! Impl from component-scan (#Service), NOT interface:
#Autowired
private TestServiceImpl testServiceImpl; // or define custom, or "inline"...
#Bean
#Primary // only if you need it, better would be: distinct!
public ProxyFactoryBean testProxyFactoryBean() {
ProxyFactoryBean testProxyFactoryBean = new ProxyFactoryBean();
// !!! set proxyInterface as documented:
testProxyFactoryBean.setProxyInterface(TestService.class);
testProxyFactoryBean.setTarget(testServiceImpl);
testProxyFactoryBean.setInterceptorNames("testMethodInterceptor");
// ...
return testProxyFactoryBean;
}
}
..enjoy! ;)

Mockito Spring Camel #Autowire fail

I'm trying to unit test a camel route. The route under test extends a custom abstract RouteBuilder (I know about favouring composition over inheritance - this is maintenance code). I've set up my test as #Roman Vottner did over here. Everything works (is initialized) until I hit the first abstract class up the hierarchy. It has an #Autowired class which wasn't initialized (is null) even though it was mocked and #Autowired when the test started. Any ideas on how to solve my injection problem?
#RunWith(CamelSpringRunner.class)
#BootstrapWith(CamelTestContextBootstrapper.class)
#ContextConfiguration(loader = AnnotationConfigContextLoader.class, classes = {FooRouteTest.ContextConfig.class})
#DirtiesContext(classMode = DirtiesContext.ClassMode.AFTER_CLASS)
public class FooRouteTest {
#Configuration
#PropertySource({"classpath:some.properties", "classpath:environment.properties"})
public static class ContextConfig extends CamelConfiguration {
#Bean
public UserServices userServices() {
return mock(UserServices.class);
} //and many more of the like
}
#Autowired
private UserServices userServices; //and all the others too
#Test
public void testAfoo() throws Exception {
//....
template.setDefaultEndpointUri("direct://getTheData");
template.sendBody(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonNode));
//...
}
}
in the abstract super class while debugging:
#Autowired
public ClientServices clientServices;
//...
String clientNumber=clientServices.getLoggedInNumber(); //clientServices is null and not mocked!
//...
Solved this by explicitly declaring FooRoute as a bean:
#Bean
public FooRoute fooRoute(){
return new FooRoute();
}
#Override
public List<RouteBuilder> routes() {
final List<RouteBuilder> routes = new ArrayList<>();
routes.add(fooRoute());
return routes;
}

Excluding an ApplicationListener #Component in Spring Boot during tests

I am trying to have my test unit up and running, and I have encountered a weird issue. My application uses an ApplicationListener class annotated as a #Component to perform an operation during startup.
During tests I have mocked the service that contains the logic, but I found that even though Mockito's when instructions work well in controller scope, the bean is not initialized for this ApplicationListener class: instead of returning what I define in the test unit, it returns either false or null - depending on the data type returned by each method in the service.
Since I have not found any way to initialize the mocked service from the test unit for the ApplicationListener class, I have decided to exclude it. To do so I have tried different approaches, being the one most often used that of creating a test application context and change its configuration. Unfortunately, nothing I have seen is working - so I am here asking for help. If possible, I would prefer not touching the ApplicationListener class and do all related coding in the test code.
I am interested in any of the two possible solutions, if they can be done:
1.- Get the mocked behaviour during the ApplicationListener execution, but I have read somewhere that this cannot be done
2.- Exclude the #Component from the test unit somehow.
TestUnit.Java:
#RunWith(SpringRunner.class)
#SpringBootTest(classes = TestApplication.class, webEnvironment = WebEnvironment.RANDOM_PORT)
#AutoConfigureMockMvc
public class TestConfigurationService {
private MockMvc mockMvc;
#Autowired
private WebApplicationContext webApplicationContext;
#MockBean
private MockService mockService;
private void initMockBean () throws Exception {
when(mockService.isDoingSomething()).thenReturn(true);
}
#Before
public void setup() throws Exception {
// Spring mock context application setup
this.mockMvc = webAppContextSetup(webApplicationContext).build();
// Initialize ConsulService mock bean
initMockBean ();
}
}
TestApplication.java
#SpringBootApplication
#EnableAutoConfiguration
#ComponentScan(basePackages="my.base.package", excludeFilters = #Filter(type = FilterType.ASSIGNABLE_TYPE, classes = StartupConfiguration.class))
public class TestApplication {
public static void main(String[] args) {
SpringApplication.run(TestApplication.class, args);
}
}
Besides what is shown in the code, I have also tried this annotation in file TestApplication.java:
#SpringBootApplication(exclude={StartupConfiguration.class})
StartupConfiguration.java
#Component
public class StartupConfiguration implements ApplicationListener<ContextRefreshedEvent> {
#Autowired
private ConfigurationService configurationService;
#Override
public void onApplicationEvent(final ContextRefreshedEvent event) {
try {
configurationService.updateConfiguration();
} catch (Exception e) {
throw new RuntimeException ("Error", e);
}
}
}
ConfigurationService.java
public interface ConfigurationService {
public void updateConfiguration () throws Exception;
}
ConfigurationServiceImpl.java
#Service
#Transactional
public class ConfigurationServiceImpl implements ConfigurationService {
#Autowired
private MService mockService;
#Override
public void updateConfiguration() throws Exception {
if (mockService.isDoingSomething()==false)
throw new Exception ("Something went wrong");
}
}
Versions:
Spring Boot 1.5.4.RELEASE,
Java 1.8
You can create mock bean of the same type and mark it with #Primary annotation to replace real bean. You can achieve this by having test such configuration:
#Configuration
#Import(TestApplication.class)
public class TestConfiguration {
#Bean
#Primary
public ConfigurationService configurationService() {
return Mockito.mock(ConfigurationService.class);
}
}
then get this mock in test:
...
public class TestConfigurationService {
...
#Autowired
ConfigurationService configurationService;
#Before
public void setUp() {
when(mockService.isDoingSomething()).thenReturn(true);
}
}
Thanks, araxn1d. Your answer gave me the clue to solve this issue.
I mocked the StartupConfiguration class in TestUnit.java:
#MockBean
private StartupConfiguration startupConfiguration;
Though in this case I was lucky: application listeners don't have returning methods, so they don't need when test configuration. If I had required that some method there returned for example true or a value, this method would not apply.
But at least for application listeners, this is enough.

Mocking Spring bean's method behavior breaks aspects

I searched SO and found bunch of other questions that looked similar but not exactly, so I'll ask another one.
I have Spring application and say I created custom aspect (looking for CatchMe annotation) to log exceptions in a specific way. I want to test the aspect by mocking the behavior of one of my Spring #Service class's method so it throws exception when it is called. Then in another method, annotated with my custom annotation #CatchMe, I call the first method. What I expect to happen is the exception to get logged. Unfortunatelly the exception is thrown but the aspect is not triggered. So how can I make the aspect to get triggered in this test using Mockito?
Note: I've checked those (plus a bunch more):
Unit testing Spring #Around AOP methods
Spring Aspect not triggered in unit test
Spring: cannot inject a mock into class annotated with the #Aspect annotation
but most of them are Controller related and not Service related and I want to test only the service.
The Test
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = {BeanConfig.class})
public class MyServiceTest {
#Autowired
#InjectMocks
private MyService service;
#Mock
private MyServiceDependency serviceDep;
#Before
public void setUp() throws Exception {
MockitoAnnotations.initMocks(this);
ReflectionTestUtils.setField(service, "serviceDep", serviceDep);
}
#Test
public void test() {
when(serviceDep.process()).thenAnswer(new Answer<Object>() {
#Override
public Object answer(InvocationOnMock invocationOnMock) throws Throwable {
throw new Exception("Sample message.");
}
});
service.execute();
}
}
Services
#Service
public class MyService {
#Autowired
private MyServiceDependency serviceDep;
#CatchMe
public void execute() {
serviceDep.process();
}
}
#Service
public class MyServiceDependency {
public Object process() {
// may throw exception here
}
}
Configuration and Aspect
#Configuration
#EnableAspectJAutoProxy
#ComponentScan(basePackages = {"com.example.services"})
public class BeanConfig { .. }
#Aspect
#Component
public class CatchMeAspect {
#Around("#annotation(CatchMe)")
public Object catchMe(final ProceedingJoinPoint pjp) throws Throwable {
try {
pjp.proceed();
} catch (Throwable t) {
// fency log
}
}
}
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.METHOD)
public #interface CatchMe {}
EDIT: The functionality works but I want to verify it with the test.
Actually it is working as expected, however you are running in a side effect of proxy based AOP, especially class based proxies in this case.
Currently you are setting the field on the proxy and not on the actual object inside the proxy. Which is what you actually want. To obtain the actual instance use AopTestUtils.getUltimateTargetObject and then use that in the ReflectionTestUtils.setField method.
#Autowired
#InjectMocks
private MyService service;
#Mock
private MyServiceDependency serviceDep;
#Before
public void setUp() throws Exception {
MockitoAnnotations.initMocks(this);
MyService serviceToInject = AopTestUtils.getUltimateTargetObject(service);
ReflectionTestUtils.setField(serviceToInject, "serviceDep", serviceDep);
}
However I think that approach is wrong, when you start messing around like this there is a better way. Simply use Spring to inject the mock. Create a specific #Configuration class for this test case. Make it a internal public static class and for the dependency add a mocked #Bean.
#Configuration
#Import(BeanConfig.class)
public static class TestBeanConfig {
#Bean
public MyServiceDependency myServiceDependency() {
return Mockito.mock(MyServiceDependency.class);
}
}
Now in your test class you can simply #Autowire both beans and not need to use reflection or whatever to set dependencies.
#RunWith(SpringJUnit4ClassRunner.class)
public class MyServiceTest {
#Autowired
private MyService service;
#Autowired
private MyServiceDependency serviceDep;
#Test
public void test() {
when(serviceDep.process()).thenAnswer(new Answer<Object>() {
#Override
public Object answer(InvocationOnMock invocationOnMock) throws Throwable {
throw new Exception("Sample message.");
}
});
service.execute();
}
}
Which will take care of the correct dependencies.
I had the same problem as #nyxz and this is intentional, see https://github.com/spring-projects/spring-boot/issues/7243.
Inspired by #M. Deinum following solution worked for me with Spring Boot 2.3.4.RELEASE and JUnit 5.
We will just provide a mocked bean without #MockedBean
#SpringBootTest
#DirtiesContext(classMode = DirtiesContext.ClassMode.AFTER_EACH_TEST_METHOD)
class MyServiceTest {
#Autowired
private MyService service;
#Test
public void test() {
service.execute();
}
static class TestBeanConfig {
#Bean
#Primary
public MyServiceDependency myServiceDependency() {
MyServiceDependency myServiceDependency = Mockito.mock(MyServiceDependency.class)
// Add behavior of mocked bean here
return myServiceDependency;
}
}
}

How to prevent Spring from injecting #Autowired references inside a mock?

I want to test a class using Spring + JUnit + Mockito but I don't manage to make it work properly.
Let's say my class references a Service:
#Controller
public class MyController
{
#Autowired
private MyService service;
#PostConstruct
public void init() {
service.whatever();
}
public void doSomething() {
service.create();
}
}
And this Service references a Repository:
#Service
public class MyService {
#Autowired
private MyRepository repository;
public void whatever() {}
public void create() {
repository.save();
}
}
When testing the MyController class, I want the service to be mocked. The problem is: even when the service is mocked, Spring tries to inject the repository in the mock.
Here is what I did. Test class:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = { MyControllerTestConfiguration.class })
public class MyControllerTest {
#Autowired
private MyController myController;
#Test
public void testDoSomething() {
myController.doSomething();
}
}
Configuration class:
#Configuration
public class MyControllerTestConfiguration {
#Bean
public MyController myController() {
return new MyController();
}
#Bean
public MyService myService() {
return Mockito.mock(MyService.class);
}
}
And the error I get: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [test.test.MyRepository] found for dependency
I tried to initialize the mock using Mockito's #InjectMocks annotation but this fails because the #PostConstruct method is called before the mocks injection, generating a NullPointerException.
And I cannot simply mock the repository because in real life that would make me mock A LOT of classes...
Can anyone help me on this?
Use constructor instead of field injection. That makes testing a lot easier.
#Service
public class MyService {
private final MyRepository repository;
#Autowired
public MyService(MyRepository repository) {
this.repository = repository;
}
public void whatever() {}
public void create() {
repository.save();
}
}
-
#Controller
public class MyController {
private final MyService service;
#Autowired
public MyController(MyService service) {
this.service = service;
}
#PostConstruct
public void init() {
service.whatever();
}
public void doSomething() {
service.create();
}
}
This has several advantages:
You don't need Spring in your tests. This allows you to do proper unit tests. It also makes the test incredibly fast (from seconds to milliseconds).
You cannot accidentally create an instance of a class without its dependencies which would result in a NullPointerException.
As #NamshubWriter pointed out:
[The instance fields for the dependencies] can be final, so 1) they cannot be accidentally modified, and 2) any thread reading the field will read the same value.
Discard the #Configuration class and write a test like this:
#RunWith(MockitoJUnitRunner.class)
public class MyControllerTest {
#Mock
private MyRepository repository;
#InjectMocks
private MyService service;
#Test
public void testDoSomething() {
MyController myController = new MyController(service);
myController.doSomething();
}
}
Use interfaces, especially if you use some kind of AOP (transactions, security, etc), i.e. you'll have interface MyService and class MyServiceImpl.
In configuration you'll have:
#Bean
public MyService myService() {
return Mockito.mock(MyService.class);
}
you should put the #InjectMocks annotation in your controller and #Mock in your service, look:
#Autowired
#InjectMocks
private MyController myController;
#Autowired
#Mock
private MyService myService;
#Before
public void setup() {
MockitoAnnotations.initMocks(this);
}
#Test
public void testDoSomething() {
myController.doSomething();
}

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