NullPointerException in the BeforeClass (spring boot) - spring-boot

Question

I want to make an insert in my DB before all tests just once. That's what I'm trying to do in the setUp() method. But got nullpointer. Spring boot version is 1.5.1.RELEASE. Any ideas?
This is from my test class:
#Autowired
private static UserRepository userRepository;
#BeforeClass
public static void setUp() {
User user = User.
.builder()
.id(10)
.name("John")
.build();
userRepository.deleteAll(); //NullPointerException at this step
userRepository.save(user);
}
This is my entity class:
#Entity
#Table(schema="test", name = "TBL_USERS")
#AllArgsConstructor
#Builder
#Data public class User implements Persistable<String>{
#Id
#Column(name = "ID", columnDefinition = "decimal")
private String id;
#Column(name = "NAME", columnDefinition = "char", nullable = false)
private String name;
...
}
This is the interface:
public interface UserRepository extends JpaRepository<User, String> {}
The stack trace:
java.lang.NullPointerException
at com.company.myapp.get.GetUserTest.setUp(GetUserTest.java:58)
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:497)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
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:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

Answer 1

Short answer: You can not inject static UserRepository (#Autowired)
Please read here Reason we could not inject static field

Answer 2

It doesn't look like you initialized userRepository to anything in your beforeClass method before calling deleteAll() on it. That's why you got your NPE.

Answer 3

Is your test class annotated with #RunWith(SpringRunner.class)?

Answer 4

You need to do something like this..
#RunWith(SpringRunner.class)
#SpringBootTest
public class XXXTest {
#Autowired
private UserRepository userRepository;
#Before
public void setUp() {
......
}