Java HTTP Servlet returns 405 despite implementing doPost

Here is the HTML code:

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>Add Two Numbers</title>
    </head>
    <body>
        <h1>Please enter numbers</h1>
        <form action="AddNum" method="post">
            Enter 1st Number :<br>
            <input type=text name=num1><br><br>
            Enter 2nd Number :<br>
            <input type=text name=num2><br><br>
            <input type="submit">
        </form>
    </body>
</html>

Here is the java code:

package com.package1;

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

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

@WebServlet("/AddNum")
public class Addserv extends HttpServlet{
    
    private static final long serialVersionUID = 1L;

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub
        super.doPost(req, resp);
        int no1=Integer.parseInt(req.getParameter("num1"));
        int no2=Integer.parseInt(req.getParameter("num2"));
        int sum=no1+no2;
        
        PrintWriter out = resp.getWriter();
        
        out.println(sum);
    }
    
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req,resp);
    }

}

even though I used the doPost method, I am getting this error message.

I am using Eclipse for IDE and Apache Tomcat 10.1.30 as my server

I tried to add a doget method(still in code as I believe it doesn't negatively alter anything)

Tried changing the method of the form to "get", same 405 error with get instead of post.

Solution

The default implementation of doPost is to return an HTTP 405 error, and it should be overridden to get a different behavior. However, by calling super.getPost, you're generating that error again.

Long story short - remove the call to the super's method and you should be OK:

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    // call to super.doPost remove from here
    int no1=Integer.parseInt(req.getParameter("num1"));
    int no2=Integer.parseInt(req.getParameter("num2"));
    int sum=no1+no2;
    
    PrintWriter out = resp.getWriter();
    
    out.println(sum);
}