erro ao carregar http://localhost:8080/gerenciadorweb/oi | Java Servlet: programação web Java

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ao carregar o http://localhost:8080/gerenciadorweb/bem-vindo.html, funcioana blz.

O erro ocorre somente ao carregar o http://localhost:8080/gerenciadorweb/oi

HTTP Status 404 – Not Found
Type Status Report

Message /gerenciadorweb/oi

Description The origin server did not find a current representation for the target resource or is not willing to disclose that one exists.

Apache Tomcat/9.0.12

Classe Servlet está igual ao curso.

package br.com.alura.gerenciadorweb.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(urlPatterns="/oi")
public class OiMundoServlet extends HttpServlet {

   private static final long serialVersionUID = 1L;

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws IOException {

        PrintWriter out = resp.getWriter();
        out.println("<html>");
        out.println("<body>");
        out.println("oi mundo, parabens vc escreveu a primeira servlet.");
        out.println("</body>");
        out.println("</html>");

        System.out.println("a servlet OiMundoServlet foi chamado");
    }
}

Web.xml criado automaticamente.

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    <display-name>gerenciadorweb</display-name>


    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>