Mockito not working for inner method variable of HttpURLConnection

this is the method for which junit is written

public boolean isSelfServicePortalServerAvailable(String crmEndPoint) {
        boolean isServerAvailable = false;
        URL url = null;
        HttpURLConnection connection = null;
        try {
            url = new URL(crmEndPoint);
            connection = (HttpURLConnection) url.openConnection();
            connection.connect();
            isServerAvailable = true;
            connection.disconnect();
        } catch (MalformedURLException e) {
            log.error(e.getMessage());
        } catch (IOException e) {
            log.error(e.getMessage());
        }
        return isServerAvailable;
    }

This is the test case wriiten

@Mock
private URL mockUrl;

@Mock
private HttpURLConnection mockConnection;

@Mock
private ISelfServiceDao selfServiceDao;

@Mock
private RestTemplate restTemplate;

@InjectMocks
private SelfServiceCoreClaimImpl selfServiceCoreClaimImpl = new SelfServiceCoreClaimImpl(restTemplate);



@Test
public void testIsSelfServicePortalServerAvailable_Success() throws IOException {
    
    when(mockUrl.openConnection()).thenReturn(mockConnection);
    doNothing().when(mockConnection).connect();
    doNothing().when(mockConnection).disconnect();

    boolean result = selfServiceCoreClaimImpl.isSelfServicePortalServerAvailable("http://test-url.com");
    assertTrue(result);
}

errors org.mockito.exceptions.misusing.UnnecessaryStubbingException: Unnecessary stubbings detected. Clean & maintainable test code requires zero unnecessary code. Following stubbings are unnecessary (click to navigate to relevant line of code):

1. -> at com.acentra.ssp.impl.SelfServiceCoreClaimImplTest.testIsSelfServicePortalServerAvailable_Success(SelfServiceCoreClaimImplTest.java:71)
2. -> at com.acentra.ssp.impl.SelfServiceCoreClaimImplTest.testIsSelfServicePortalServerAvailable_Success(SelfServiceCoreClaimImplTest.java:72)
3. -> at com.impl.SelfServiceCoreClaimImplTest.testIsSelfServicePortalServerAvailable_Success(SelfServiceCoreClaimImplTest.java:73) Please remove unnecessary stubbings More info: javadoc for UnnecessaryStubbingException class. at org.mockito.junit.jupiter.MockitoExtension.afterEach(MockitoExtension.java:192) at java.base/java.util.ArrayList.forEach(ArrayList.java:1511) at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)

Not calling mock ... can someone help me on this

I would try:

    public boolean isSelfServicePortalServerAvailable(String crmEndPoint) {
        boolean isServerAvailable = false;
        try {
            HttpURLConnection connection = getHttpURLConnection(crmEndPoint);
            connection.connect();
            isServerAvailable = true;
            connection.disconnect();
        } catch (MalformedURLException e) {
            log.error(e.getMessage());
        } catch (IOException e) {
            log.error(e.getMessage());
        }
        return isServerAvailable;
    }

    private HttpURLConnection getHttpURLConnection(String crmEndPoint) throws IOException {
        URL url = new URL(crmEndPoint);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        return connection;
    }

And then test

    @Mock
    private HttpURLConnection mockConnection;

    @Mock
    private ISelfServiceDao selfServiceDao;

    @Mock
    private RestTemplate restTemplate;

    @InjectMocks
    @Spy
    private SelfServiceCoreClaimImpl selfServiceCoreClaimImpl;



    @Test
    public void testIsSelfServicePortalServerAvailable_Success() throws IOException {
        String crmEndPoint = "http://test-url.com";
        doReturn(mockConnection).when(selfServiceCoreClaimImpl).getHttpURLConnection(crmEndPoint);
        doNothing().when(mockConnection).connect();
        doNothing().when(mockConnection).disconnect();

        boolean result = selfServiceCoreClaimImpl.isSelfServicePortalServerAvailable(crmEndPoint);
        assertTrue(result);
    }