What might be a reason for NullPointerException of jobLauncherTestUtils? (Spring Batch)

Question

I have a job with a step and when I attempt to test this job with JobLauncherTestUtils, I get the following exception:

java.lang.NullPointerException
at io.spring.cdrreader.CdrReaderApplicationTests.testJob(CdrReaderApplicationTests.java:32)
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$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)

I have searched on net and tried many ways to solve this problem but these did not work.

Test class:

@ExtendWith(SpringExtension.class)
@SpringBatchTest
@ContextConfiguration(classes = {Config.class})
public class CdrReaderApplicationTests {

@Autowired
private JobLauncherTestUtils jobLauncherTestUtils;

@Test
public void testJob() throws Exception {

    JobParameters jobParameters =
            jobLauncherTestUtils.getUniqueJobParameters();

    JobExecution jobExecution =
            jobLauncherTestUtils.launchJob(jobParameters);

    Assert.assertEquals(ExitStatus.COMPLETED,
            jobExecution.getExitStatus());
}

}

Initialization of JobLauncherTestUtils with a job in config class:

    @Bean
    public JobLauncherTestUtils getJobLauncherTestUtils() {

    return new JobLauncherTestUtils() {
        @Override
        @Autowired
        public void setJob(@Qualifier("demoJob") Job job) {
            super.setJob(job);
        }
    };
}

Answer 1

You are running the test as JUnit 4 test (see Stacktrace com.intellij.junit4.JUnit4IdeaTestRunner), however your test is annotated with @ExtendWith(SpringExtension.class), which is JUnit 5 API.

This leads to Spring testing extensions (like @SpringBatchTest) not getting picked up, because the Spring extension/runner is not registered. This results in the NPE (@Autowired functionality doesnt work).

So you either change this to @RunWith(SpringRunner.class) or you start the test as JUnit 5 test.

Example as JUnit 4 Test:

@RunWith(SpringRunner.class)
@SpringBatchTest
@ContextConfiguration(classes = {Config.class})
public class CdrReaderApplicationTests {
   // ...
}