import jakarta.servlet.ServletException;import jakarta.servlet.annotation.WebServlet;import jakarta.servlet.http.HttpServlet;import jakarta.servlet.http.HttpServletRequest;import jakarta.servlet.http.HttpServletResponse;import java.io.IOException;import java.io.PrintWriter;public class PostServlet4 extends HttpServlet { private static final long serialVersionUID = 1L; protected void doPost(HttpS..