Create HttpClient using PoolingHttpClientConnectionManager

I have a java service class which will call a REST service and get response back.
It is working fine in developer environment where less requests are made, but I still wanted to get a review.

My service method call is like:

private String getResponse(Object request, String cUri) {
String responseStr = StringUtils.EMPTY;
    try {

        Gson requestJson = new GsonBuilder().disableHtmlEscaping().create();
        String inputJson =  requestJson.toJson(request);
        logger.debug("Input JSON : " + inputJson);

        responseStr = connect.getResponse(cUri, inputJson,config.getHttpClient());
        logger.debug("Outut JSON for provided request" + responseStr);

    } catch (Exception e) {
        logger.error("Exception while getting response from service : " + e,e);
    }
    return responseStr;
}

Here config.getHttpClient()); is as follows:

public class Test {

    private static CloseableHttpClient httpClient;
    private static PoolingHttpClientConnectionManager connectionManager;

    public CloseableHttpClient getHttpClient() {

        if(httpClient != null){
            return httpClient;
        }

        try {

            SSLContext sslContext = getSSLContext();

            SSLConnectionSocketFactory trustSelfSignedSocketFactory = new SSLConnectionSocketFactory(
                    sslContext == null 
                    ? SSLContext.getDefault() : sslContext
                            ,new String[] { "TLSv1", "TLSv1.2", "TLSv1.1" }
                            ,null
                            ,NoopHostnameVerifier.INSTANCE);

            Registry<ConnectionSocketFactory> socketFactoryRegistry= RegistryBuilder.<ConnectionSocketFactory>create()
                    .register("https", trustSelfSignedSocketFactory)
                    .register("http", PlainConnectionSocketFactory.getSocketFactory()).build();

            connectionManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
            connectionManager.setMaxTotal(Integer.parseInt(props.getProperty(Constants._CONNECTION_COUNT)));
            connectionManager.setDefaultMaxPerRoute(Integer.valueOf(props.getProperty(Constants._MAX_PER_ROUTE)));

            httpClient = HttpClientBuilder
                    .create()
                    .setConnectionManager(connectionManager)
                    .setConnectionManagerShared(true)
                    .build();

        } catch (Exception e) {
            logger.error("Error in getting rest server connection" + e, e);
        }

        return httpClient;

    }

    private SSLContext getSSLContext(){
        //return sslContext;
    }

}

And this Test class is initialized as Singleton bean.

And public String getResponse(String uri, String inputJson, CloseableHttpClient httpClient) is as follows:

public class ConnectionHelper{

    public String getResponse(String uri, String inputJson, CloseableHttpClient httpClient) throws Exception{

        String responseStr = StringUtils.EMPTY;
        HttpPost request = new HttpPost(uri);
        StringEntity params = new StringEntity(inputJson);
        request.addHeader("Content-type", "application/json");
        request.setEntity(params);

        try(final CloseableHttpResponse response= httpClient.execute(request)){
            responseStr = EntityUtils.toString(response.getEntity(),"UTF-8");
        }catch(Exception e){
            logger.error("Error while exeucting on request " + e,e);
        }finally {
            httpClient.close();
        }

        return responseStr;
    }

}