JTable object.getModel（）返回nullpointer异常

Question

我正在尝试填充JTable对象，但是当指令 private final DefaultTableModel tarifModel = (DefaultTableModel) tbTarife.getModel();被调用，我收到了NullPointerException。

我正在使用Netbeans 8.2和GUI Builder插件来创建JTable。

我已经实现了here中描述的部分，而涉及此问题的其他任何问题似乎都不适用。

我的代码：

public class TarifDialog extends javax.swing.JPanel {

    private final TarifParser tP;

    public TarifDialog() {

         initComponents();
         tP = new TarifParser(this);

    }

    //Generated code
    private void initComponents() {

        tbTarife = new javax.swing.JTable();
        scrollpTarife = new javax.swing.JScrollPane();

        tbTarife.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {

            },
            new String [] {
                "Schlüssel", "Name", "Beschreibung", "Preis", "Typ"
            }
        ) {
            boolean[] canEdit = new boolean [] {
                false, false, false, false, false
            };

            public boolean isCellEditable(int rowIndex, int columnIndex) {
                return canEdit [columnIndex];
            }
        });
        scrollpTarife.setViewportView(tbTarife);
    }

    private javax.swing.JScrollPane scrollpTarife;
    private javax.swing.JTable tbTarife;
    //End generated code

    private final DefaultTableModel tarifModel = (DefaultTableModel) tbTarife.getModel();

    public void addTarifToTable(String Key, String name, String description, double price, String type) {     
        tarifModel.addRow(new Object[]{Key, name, description, price, type});
    }
}

以及访问它的类：

public final class TarifParser {
    private final TarifVerwaltung tV;
    private final TarifDialog tD;

    public TarifParser(TarifDialog tD) {
        this.tV = Init.getTarifVerwaltung();
        this.tD = tD;
        populateTarifTable();
    }

    public void populateTarifTable() {
        for (HashMap.Entry<String, Tarif> tariff : tV.getAllTariffs().entrySet()) {
            String type = "Undefined";
            if (tariff.getValue().getType() == 0) {
                type = "Standard Tarif";
            } else if (tariff.getValue().getType() == 1) {
                type = "Wiederkehrender Tarif";
            } else if (tariff.getValue().getType() == 2) {
                type = "Einmaliger Tarif";
            }
            tD.addTarifToTable(tariff.getKey(), tariff.getValue().getName(), tariff.getValue().getDescription(), tariff.getValue().getPrice(), type);
        }
    }
}