Mock a method inside autowired component using Spring, JUnit and Mockito

I'm looking for a way to "mock" a method inside an Autowired component.

For example, my PersistService contains a method like:

@Autowired
    MeterManagementService meterManagementService;

@Transactional(propagation = Propagation.REQUIRED, rollbackFor = Exception.class)
    @Override
    public void doPersist(HouseholdUpdateServiceCall householdUpdateServiceCall) throws Exception {
        LOG.info("doPersist start()");
        if (householdUpdateServiceCall.getHhId() > -1) {
            saveUboPanelInfo(householdUpdateServiceCall);
            saveUboSites(householdUpdateServiceCall);
            if (householdUpdateServiceCall.getHouseholdUpdateRequest() != null
                    && householdUpdateServiceCall.getHouseholdUpdateRequest().getPeopleMeter() != null
                    && householdUpdateServiceCall.getHouseholdUpdateRequest().getPeopleMeter().getPeople() != null
                    && householdUpdateServiceCall.getHouseholdUpdateRequest().getPeopleMeter().getPeople().getPerson() != null) {
                
                Integer panelId = new Long(householdUpdateServiceCall.getPanelId()).intValue();
                Integer hhId = new Long(householdUpdateServiceCall.getHhId()).intValue();
                Integer personCount = householdUpdateServiceCall.getHouseholdUpdateRequest().getPeopleMeter().getPeople().getPerson().size();
                
                LOG.info("storePersonCount for panelId: " + panelId + ", hhId: " + hhId + ", personCount: " + personCount);
                uboPanelDao.storePersonCount(hhId, personCount, panelId);
            }
        
        String result = meterManagementService.getResult();
        LOG.info("The result is: " + result);     
        LOG.info("doPersist end()");
        }
    }

The Junit test contains:

    @Autowired
PersistService persistService;
//normal success scenario
@Test
public void test03() {
try {
HouseholdUpdateServiceCall householdUpdateServiceCall = new HouseholdUpdateServiceCall();
householdUpdateServiceCall.setCPCount(0);
householdUpdateServiceCall.setHhId(1L);
householdUpdateServiceCall.setPanelId(1L);
//how to mock the method which is used inside doPersist and it is autowired in persistService?
persistService.doPersist(householdUpdateServiceCall);
...

What I'm looking for is how to mock a method (String result = meterManagementService.getResult()) inside the persistService? For example how to set a value "OK" for meterManagementService.getResult()?

Thank you for any advice and help

You can just use @MockBean in your test like this (if @RunWith(SpringRunner.class))

@MockBean private MeterManagementService meterManagementService

It will be mocked and injected.

If you are not using or you cannot use SpringRunner use constructor/setter to set your dependencies - there you will be able to provide mocked instances and use it at will.