Java com Oracle

Connection conn = Conexao.getInstance().getConnection();
            try {
                String sql = "SELECT IBGE, estado from arqmunic where nome = 'TEUTONIA'";
                Statement sta = conn.createStatement();
                ResultSet rs = sta.executeQuery(sql);
                while (rs.next()) {
                    codMuniDest = String.valueOf(rs.getString(1));
                    ufDest = rs.getString(2);
                }
            } catch (SQLException e) {
                System.err.println(e);
            }

07/08/2009 14:10:39 ui.EnviarNota btnEnviarActionPerformed
SEVERE: null
java.lang.NullPointerException

Statement sta = conn.createStatement();