How can I make powermock work with Java11? - powermock

Question

I have a service project written in Java11. It is using junit tests to cover full code coverage.
I have written scheduler method to updateFiles (invoked by Files.walkFileTree) in FileReceivingStateMarkerService class. I want to test static call Files.walkFileTree from test class written for FileReceivingStateMarkerService. I need to use PowerMockRunner to test static call as it cannot be tested by simple MockitoJunitRunner.
On running test, I am getting NPE in setUp method at line - mockStatic(Files.class);
Can you please help me to resolve issue on how to configure powermock with Java11 and initialize static class?
I configured powermock in service project (in Java11) as below
<dependency>
<groupId>org.powermock</groupId>
<artifactId>powermock-module-junit4</artifactId>
<version>2.0.0-RC.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.powermock</groupId>
<artifactId>powermock-api-mockito2</artifactId>
<version>2.0.0-RC.1</version>
<scope>test</scope>
</dependency>
FileReceivingStateMarkerService class
class FileReceivingStateMarkerService {
private static final Logger LOG = LoggerFactory.getLogger(FileReceivingStateMarkerService.class);
private final FileProcessingActivityRepositoryService fileProcessingActivityRepositoryService;
private final FilePollActivityRepository filePollActivityRepository;
private final FileProcessingRequestRepositoryService fileProcessingRequestRepositoryService;
#Autowired
FileReceivingStateMarkerService(FileProcessingActivityRepositoryService fileProcessingActivityRepositoryService, FilePollActivityRepository filePollActivityRepository,
FileProcessingRequestRepositoryService fileProcessingRequestRepositoryService) {
this.fileProcessingActivityRepositoryService = fileProcessingActivityRepositoryService;
this.filePollActivityRepository = filePollActivityRepository;
this.fileProcessingRequestRepositoryService = fileProcessingRequestRepositoryService;
}
#Scheduled(fixedDelayString="#{${fileprocess.filemonitor.interval.minutes}*60*1000}")
void updateFiles() {
List<FileProcessingRequest> requests = fileProcessingRequestRepositoryService.getFileProcessingRequests();
LOG.debug("Running file receiving state");
requests.forEach(request -> {
LOG.debug("Looking at location {}", request.getFileLocation());
final var fileVisitor = new FileReceivingStateMarkerFileVisitor(filePollActivityRepository
, fileProcessingActivityRepositoryService
, request);
try {
Files.walkFileTree(Path.of(request.getFileLocation()), Collections.emptySet(), 1, fileVisitor);
} catch(Exception e) {
LOG.debug(e.getMessage());
}
});
}
}
Test class for FileReceivingStateMarkerService
package com.experianhealth.rfp.scheduler;
import com.experianhealth.rfp.core.DocumentType;
import com.experianhealth.rfp.core.FileProcessingRequest;
import com.experianhealth.rfp.dao.FilePollActivityRepository;
import com.experianhealth.rfp.service.FileProcessingActivityRepositoryService;
import com.experianhealth.rfp.service.FileProcessingRequestRepositoryService;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PowerMockIgnore;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import static org.mockito.ArgumentMatchers.any;
import static org.powermock.api.mockito.PowerMockito.mockStatic;
#RunWith(PowerMockRunner.class)
#PowerMockIgnore({"com.sun.org.apache.xerces.*", "javax.xml.*", "org.xml.*", "org.w3c.*"})
#PrepareForTest(FileReceivingStateMarkerService.class)
public class FileReceivingStateMarkerServicePowerTest {
#Mock
private FileProcessingActivityRepositoryService fileProcessingActivityRepositoryService;
#Mock
private FilePollActivityRepository filePollActivityRepository;
#Mock
private FileProcessingRequestRepositoryService fileProcessingRequestRepositoryService;
#Before
public void setUp() throws Exception {
mockStatic(Files.class);
}
#Test
public void updateFiles() throws Exception {
String rootDir = "C:\\files_processor";
List<FileProcessingRequest> requests = new ArrayList<>();
FileProcessingRequest request = new FileProcessingRequest();
request.setClientId("123");
request.setTradingPartnerId("123");
request.setDocumentId(DocumentType.Payer);
request.setFileLocation(rootDir);
requests.add(request);
final var fileVisitor = new FileReceivingStateMarkerFileVisitor(filePollActivityRepository
, fileProcessingActivityRepositoryService
, request);
try {
PowerMockito.when(Files.walkFileTree(Path.of(request.getFileLocation() ), Collections.emptySet(), 1, fileVisitor))
.thenReturn(any());
} catch(Exception e) {
System.out.println(e.getMessage());
}
}
}