Trying to implement an SQL vulnerability in a java web application. Java + MySQL

This is a bit of an odd one. For my uni final project I'm trying to develop a vulnerable web application as an educational tool. One of the vulnerabilities I want to implement is an SQL vulnerability where the user could perform an SQL injection through a 'product search' page on the site.

The problem is that somewhere along the way the inputs seem to be getting sanitised automatically which means I am unable to perform an injection attack. I made a test record of just a single quote (') and this is returned when a single quote in put into the search. If the input was not sanitised it would return an error, right? I'm thinking this could be a feature of the software I'm using that I'll need to disable or use an older version, or I've accidentally set it up in such a way that this is happening. If anyone knows why this might be happening, any help would be massively appreciated! :)

I have a database set up in MySQL Community Server 8.0.13 and a simple application made using JSPs. I have included source code below.

The 'Product Search' page:

<%@page import="java.sql.Connection"%>
<%@page import="databaseManagement.DBConnection"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.SQLException"%>
<%@page import="java.sql.Connection"%>
<%@page import="java.sql.PreparedStatement"%>

<?xml version="1.0" encoding="ISO-8859-1" ?>
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<title>Search Our Products</title>
</head>
<body>
    <h1>Search for a product</h1>
    <form method="post" action="ProductSearch">

        Search: <input type="text" name="Search"> <br> 
        <input type="submit" value="Go"> 

        <%@taglib uri="http://java.sun.com/jstl/core_rt" prefix="c"%><br>

                <table align="left" border="1">
                        <tr>
                            <th>ID</th>
                            <th>Name</th>
                            <th>Description</th>
                            <th>Price</th>
                        </tr>
                        <c:forEach var="product" items="${r1}">


                            <tr bgcolor="">

                                <td>${product.id}</td>
                                <td>${product.name}</td>
                                <td>${product.description}</td>
                                <td>${product.price}</td>
                            </tr>
                        </c:forEach>
                    </table>
    </form>
</body>
</html>

The java servlet:

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import databaseManagement.DBConnection;
import databaseManagement.Product;

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

    public ProductSearch() {
        super();
        // TODO Auto-generated constructor stub
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // TODO Auto-generated method stub

        String searchTerm = request.getParameter("Search");
        searchTerm = "%" + searchTerm + "%";
        ArrayList<Product> ab = new ArrayList();

        try {

            String sql1 = "select * from products where name like ?;";
            DBConnection db = new DBConnection();
            Connection con = db.getConnection();

            PreparedStatement ps = con.prepareStatement(sql1);

            ps.setString(1, searchTerm);

            ResultSet rs = ps.executeQuery();
            while (rs.next()) {

                Product b = new Product();
                b.setId(rs.getInt("id"));
                b.setName(rs.getString("name"));
                b.setDescription(rs.getString("description"));
                b.setPrice(rs.getString("price"));
                ab.add(b);
            }

            request.setAttribute("r1", ab);
            request.getRequestDispatcher("productSearch.jsp").forward(request, response);

        }

        catch (Exception s2) {
            s2.printStackTrace();
        }

    }
}

Solution

Fragment of doPost method that should be placed to accept SQL injection:

....
try {

        String sql1 = "select * from products where name like '"+searchTerm+"';";
        DBConnection db = new DBConnection();
        Connection con = db.getConnection();

        Statement ps = con.createStatement();

        ResultSet rs = ps.executeQuery();
        while (rs.next()) {

....

PreparedStatement prevents SQL Injection, so use Statement instead.