can't reuse HTTP connections

package com.jtaphie;

import java.io.InputStream;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import org.apache.commons.io.IOUtils;
import org.apache.http.client.HttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.olingo.client.api.ODataClient;
import org.apache.olingo.client.api.communication.request.retrieve.ODataEntityRequest;
import org.apache.olingo.client.api.communication.response.ODataRetrieveResponse;
import org.apache.olingo.client.api.domain.ClientEntity;
import org.apache.olingo.client.api.http.HttpClientFactory;
import org.apache.olingo.client.api.http.NoContentException;
import org.apache.olingo.client.core.ODataClientFactory;
import org.apache.olingo.commons.api.ex.ODataRuntimeException;
import org.apache.olingo.commons.api.http.HttpMethod;

public class ReuseHttpConnectionTest {

  public static void main(String[] args) throws Exception {
    ReusableHttpClientFactory httpClientFactory = new ReusableHttpClientFactory();
    ODataClient client = ODataClientFactory.getClient();
    client.getConfiguration().setHttpClientFactory(httpClientFactory);

    ODataEntityRequest<ClientEntity> request =
        client
            .getRetrieveRequestFactory()
            .getEntityRequest(
                new URI(
                    "https://services.odata.org/V4/(S(ckjlngqm5lub5c5osrvdfvbf))/TripPinServiceRW/Photos(1)"));

    ODataRetrieveResponse<ClientEntity> response = null;
    try {
      response = request.execute();
    } catch (ODataRuntimeException e) {
      // HTTP 404
    }

    if (response != null) {
      try (InputStream is = response.getRawResponse()) {
        System.out.println(IOUtils.toString(is, StandardCharsets.UTF_8));
      } catch (NoContentException e) {
        // HTTP 204
      } finally {
        response.close();
      }
    }

    System.out.print(httpClientFactory.connectionManager.getTotalStats());
  }

  private static class ReusableHttpClientFactory implements HttpClientFactory {
    private final PoolingHttpClientConnectionManager connectionManager;
    private final HttpClient httpClient;

    private ReusableHttpClientFactory() {
      connectionManager = new PoolingHttpClientConnectionManager();
      httpClient = HttpClients.custom().setConnectionManager(connectionManager).build();
    }

    @Override
    public HttpClient create(HttpMethod method, URI uri) {
      return httpClient;
    }

    @Override
    public void close(HttpClient httpClient) {
      // do nothing as we want to reuse the same http client instance
    }
  }
}