Servlet: alguem me ajuda a achar qual o meu erro?

import java.io.PrintWriter;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.UnavailableException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class conectBD extends HttpServlet{

    private Connection connection;
    private Statement statement;
    
    public void init (ServletConfig config) throws ServletException{ //configura a conexao ao bd e cria a instruçao sql
        
        try{ //tenta a conexao com o banco e  cria instrucao
            Class.forName(config.getInitParameter("com.mysql.jdbc.Driver"));
            
            connection=DriverManager.getConnection(
            config.getInitParameter("jdbc:mysql://localhost/tabela"),
            config.getInitParameter("root"),
            config.getInitParameter("rootlar"));
            
            statement = connection.createStatement();
            
        }catch(Exception e){
            e.printStackTrace();
            throw new UnavailableException(e.getMessage());
        }
    }
    //processa a resposta da busca
    protected void doPost(HttpServletRequest req,HttpServletResponse res)throws ServletException, IOException{
    
    }
}