Cannot get a connection using JDBC

Question

I have tried to build a web application using JAVA.

This is the code of connection between JDBC and MySQL server. The code did not run.

import java.sql.*;

public class RegisterDao {
    
    private String dburl = "jdbc:mysql://localhost:3306/hospitalm";
    private String dbuname = "root";
    private String dbpassword = "1234";
    private String dbdriver = "com.mysql.jdbc.Driver";
    
    public void loadDriver(String dbDriver) {
        try {
            Class.forName(dbDriver);
        } catch(ClassNotFoundException e){
            e.printStackTrace();
        }
    }
    
    public Connection getConnection() {
        Connection con = null;
        try {
            con = DriverManager.getConnection(dburl, dbuname, dbpassword);
            System.out.println("Connection was established");
        } catch(SQLException e){
            e.printStackTrace();    
        }
        
        return con;
    }
    
    public String insert(Member member) {
        loadDriver(dbdriver);

        Connection con = getConnection();
        String result = "data entered successfully";
        String sql = "insert into hospitalm.patient values(?, ?, ?, ?, ?)";
        try {
            PreparedStatement ps = con.prepareStatement(sql);
            ps.setString(1, member.getPid());
            ps.setString(2, member.getName());
            ps.setString(3, member.getAddress());
            
            ps.setString(4, member.getEmail());
            ps.setString(5, member.getType());
            ps.executeUpdate();
        } catch (SQLException e){
            e.printStackTrace();
            result = "Data not entered successfully";
        }
    
        return result;
    }
    
}

Can anyone let me know what is the error on the above code?

The SQL table is like:

CREATE TABLE patient(
    pid VARCHAR(10),
    pname VARCHAR(40) NOT NULL,
    address VARCHAR(10),
    email_id VARCHAR(20) NOT NULL,
    ptype VARCHAR(2),
    PRMARY KEY(pid),
    CHECK (email_id like '%_@__%.__%'),
    CHECK (ptype in ('G','S'))
);

I got HTTP Status 500 Internal Server error.

Type: Exception Report

Message: Cannot invoke "java.sql.Connection.prepareStatement(String)" because "con" is null

Description: The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception:

java.lang.NullPointerException: Cannot invoke "java.sql.Connection.prepareStatement(String)" because "con" is null
  RegisterDao.insert(RegisterDao.java:47)
  Register.doPost(Register.java:47)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:681)
  javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
  org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Note The full stack trace of the root cause is available in the server logs.

The servlet code that I added:

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        String Pid = request.getParameter("pid");
        String Name = request.getParameter("patientname");
        String Address = request.getParameter("patientaddress");
        
        String Email = request.getParameter("email");
        String Type = request.getParameter("patienttype");
        
        Member member = new Member(Pid, Name, Address, Email, Type);
        RegisterDao rDao= new RegisterDao();
        String result = rDao.insert(member);
        response.getWriter().print(result);
        
        
        //doGet(request, response);
    }

}

What are the possible causes of getting this type of error?