DB Helper to perform CRUD operations

DBHelper.java

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

public class DBHelper {

	Properties props = new Properties();
	Connection connection = null;
	PreparedStatement statement;
	ResultSet resultSet;

	public DBHelper() throws IOException, ClassNotFoundException, SQLException {
		props.load(DBHelper.class.getResourceAsStream("sql.properties"));
		Class.forName("org.sqlite.JDBC");
		connection = DriverManager.getConnection("jdbc:sqlite:test.db");
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {

		try {
			DBHelper db = new DBHelper();

			List list = new ArrayList();
			list.add(43134);
			list.add("dhanraj thakare");
			list.add(23);
			list.add(229.43);
			// db.updateQuery("insert", list);

			list = new ArrayList();
			list.add(44);
			db.updateQuery("delete_id", list);

			db.displayRecords();

			db.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	void displayRecords() throws SQLException {
		resultSet = selectQuery("select_all", new ArrayList<Object>());

		System.out.println("Name" + "\t" + "Salary" + "\t" + "ID" + "\t"
				+ "Age");

		while (resultSet.next()) {
			String coffeeName = resultSet.getString("NAME");
			double price = resultSet.getDouble("SALARY");
			int sales = resultSet.getInt("ID");
			int total = resultSet.getInt("AGE");
			System.out.println(coffeeName + "\t" + price + "\t" + sales + "\t"
					+ total);
		}

		resultSet.close();
		statement.close();
	}

	/**
	 * Select query to fetch results based on values
	 * 
	 * @param sql
	 *            The prepared statement sql query
	 * @param values
	 *            Values for prepared statement
	 * @return Resultset of the query
	 * @throws SQLException
	 */
	ResultSet selectQuery(String sql, List<Object> values) throws SQLException {
		prepareStatement(sql, values);
		resultSet = statement.executeQuery();
		return resultSet;
	}

	void updateQuery(String sql, List<Object> values) throws SQLException {
		prepareStatement(sql, values);
		statement.executeUpdate();
		statement.close();
	}

	void prepareStatement(String sql, List values) throws SQLException {
		statement = connection.prepareStatement(props.getProperty(sql));

		int i = 1;
		for (Object obj : values) {
			if (obj instanceof Integer) {
				statement.setInt(i++, (Integer) obj);
			} else if (obj instanceof String) {
				statement.setString(i++, (String) obj);
			} else if (obj instanceof Double) {
				statement.setDouble(i++, (Double) obj);
			} else if (obj instanceof Float) {
				statement.setFloat(i++, (Float) obj);
			}
		}

	}

	void close() throws SQLException {
		resultSet.close();
		statement.close();
		connection.close();
	}

}