public class DataBaseAddServlet extends HttpServlet{
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String url = req.getParameter("url");

        DatabaseManager dbManager = new DatabaseManager();
//        String pathInfo = req.getPathInfo().substring(1);
        String id = dbManager.AddDocument(url);
        resp.getWriter().println(id);
    }
}

    public String AddDocument(String id) {
        CouchbaseClient c = cm.getClient();

        String randomId = UUID.randomUUID().toString();
        c.add(id, randomId);
        return id;
    }

public class DatabaseIterationServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        DataBaseAddServlet dataBaseAddServlet = new DataBaseAddServlet();
        for (int k = 0; k < 100; k++) {
            dataBaseAddServlet.doGet(req, resp);
        }
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
		  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         version="2.5">

    <servlet>
        <servlet-name>DataBaseAddServlet</servlet-name>
        <servlet-class>DataBaseAddServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>DataBaseAddServlet</servlet-name>
        <url-pattern>/database/add</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>DatabaseIterationServlet</servlet-name>
        <servlet-class>DatabaseIterationServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>DatabaseIterationServlet</servlet-name>
        <url-pattern>/database/iteration</url-pattern>
    </servlet-mapping>

</web-app>

public class ConnectionManager {
    Logger logger = Logger.getLogger(getClass().getName());
    private CouchbaseClient client;

    public ConnectionManager() {
        init();
    }

    public void init() {
        try {
            logger.info("Opening base connection.");
            List<URI> hosts = Arrays.asList(new URI("http://127.0.0.1:8091/pools"));            
            String bucket = "default";          
            String password = "";          
            client = new CouchbaseClient(hosts, bucket, password);
        } catch (Exception e) {
            client = null;
            throw new IllegalStateException(e);
        }
    }
    @PreDestroy
    public void destroy() {
        logger.info("Closing base connection.");
        if (client != null) {
            client.shutdown();
            client = null;
        }
    }

    public CouchbaseClient getClient() {
        return client;
    }
}

HTTP Status 404 - /database/DataBaseAddServlet
type Status report
message /database/DataBaseAddServlet
description The requested resource is not available.

public class DatabaseManager {
    ConnectionManager cm;

    public DatabaseManager() {
        cm = new ConnectionManager();
    }

    public String AddDocument(String id) {
        CouchbaseClient c = cm.getClient();
        String randomId = UUID.randomUUID().toString();
        c.add(id, randomId);
        return id;
    }
}

public class DatabaseIterationServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        for (int k = 0; k < 100; k++) {         
            DatabaseManager dbManager = new DatabaseManager();
            String randomId = UUID.randomUUID().toString();
            dbManager.AddDocument(randomId);         
        }
    }
}