SampleServlet.java

package edu.eci.cvds.servlet;

import java.io.IOException;
import java.io.Writer;
import java.util.Optional;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(
    urlPatterns = "/helloServlet"
)
public class SampleServlet extends HttpServlet{
    static final long serialVersionUID = 35L;

    @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       Writer responseWriter = resp.getWriter();
       Optional<String> optName = Optional.ofNullable(req.getParameter("name"));
       String name = optName.isPresent() && !optName.get().isEmpty() ? optName.get() : "";

       resp.setStatus(HttpServletResponse.SC_OK);
       responseWriter.write("Hello" + name + "!");
       responseWriter.flush();
   }
}