How to use connection pools

gistfile1.java

public static ResultSet executeSingleQuery(String query) throws ConnectorException {
    Connection conn = null;
    ResultSet data = null;
    PreparedStatement stmt = null;
    try {
        conn = ConnectionFactory.LARGE.getConnection(dbDriver, dbUrl, dbUserName, dbPassword);
        log.log(Level.INFO, "Query: {0}", query);
        data = conn.prepareStatement(query).executeQuery();
    } catch (final SQLException sqle) {
        log.log(Level.INFO, "Error SQLException: {0}", sqle.getMessage());
        throw new ConnectorException(sqle, null, null);
    } finally {
        ConnectionFactory.LARGE.close(stmt);
        ConnectionFactory.LARGE.close(conn);
    }
    return data;
}