static Connection conn = null;
    static Statement stmt = null;

    public void createConnection() {
        try {
            //Connect conn = new Connect();
            conn = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:XE", "test", "test");
            stmt = conn.createStatement();
        } catch (SQLException e) {
            System.err.println("Error at create connection " + e);
        }
    }

    public void fillTable(JTable table, String Query) {
        try {
            createConnection();
            //To remove previously added rows
            try (ResultSet rs = stmt.executeQuery(Query)) {
                //To remove previously added rows
                while (table.getRowCount() > 0) {
                    ((DefaultTableModel) table.getModel()).removeRow(0);
                }
                int columns = rs.getMetaData().getColumnCount();
                while (rs.next()) {
                    Object[] row = new Object[columns];
                    for (int i = 1; i <= columns; i++) {
                        row[i - 1] = rs.getObject(i);
                    }
                    ((DefaultTableModel) table.getModel()).insertRow(rs.getRow() - 1, row);
                }
            }
            stmt.close();
            conn.close();
        } catch (SQLException e) {
            System.err.println("SQL error at fill table\n" + e);
        }
    }