PoolingHttpClientConnectionManager connManager = connManager = new PoolingHttpClientConnectionManager();
connManager.setMaxTotal(4);
    connManager.setDefaultMaxPerRoute(4);

//Creating CloseableHttpClient with a default keep alive of 2 minutes
    CloseableHttpClient  client = HttpClients.custom()
            .setConnectionManager(connManager)
            .setKeepAliveStrategy(new KeepAliveStrategy(keepAlive))
            .build();


//Sending 1st request
String xml="<xml data>";
HttpPost post = new HttpPost("<URL>");
    HttpEntity entity = new ByteArrayEntity(xml.getBytes("UTF-8"));
    post.setEntity(entity);
    HttpResponse  response =client.execute(post);
    String result = EntityUtils.toString(response.getEntity());
    EntityUtils.consume(response.getEntity());

PoolStats stats = connManager.getTotalStats();
    System.out.println("Total Connections Available : "+stats.getAvailable());