Can anyone Help?
I want to dynamically display my Database content into TableView in FXML file.
The Code works when I don't have any null Value in any of the column database.
I expected the code should display empty space in TableView of FXML when my database column has a null value.

```
dateOfIssue.setCellValueFactory(new Callback<CellDataFeatures<ObservableList, String>, ObservableValue<String>>() {
                public ObservableValue<String> call(CellDataFeatures<ObservableList, String> param) {
                    return new SimpleStringProperty(param.getValue().get(2).toString());
                }
            });
        studentID.setCellValueFactory(new Callback<CellDataFeatures<ObservableList, String>, ObservableValue<String>>() {
                public ObservableValue<String> call(CellDataFeatures<ObservableList, String> param) {
                    return new SimpleStringProperty(param.getValue().get(3).toString());
                }
            });
        primary.setCellValueFactory(new Callback<CellDataFeatures<ObservableList, String>, ObservableValue<String>>() {
                public ObservableValue<String> call(CellDataFeatures<ObservableList, String> param) {
                    return new SimpleStringProperty(param.getValue().get(0).toString());
                }
            });
        secondary.setCellValueFactory(new Callback<CellDataFeatures<ObservableList, String>, ObservableValue<String>>() {
                public ObservableValue<String> call(CellDataFeatures<ObservableList, String> param) {
                        return new SimpleStringProperty(param.getValue().get(1).toString());

                }
            });

```

I have my secondary column as null at few rows.here is my error.

```
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at library.DatabaseController$4.call(DatabaseController.java:105)
at library.DatabaseController$4.call(DatabaseController.java:103)
at javafx.scene.control.TableColumn.getCellObservableValue(TableColumn.java:578)
at javafx.scene.control.TableColumn.getCellObservableValue(TableColumn.java:563)
at javafx.scene.control.TableCell.updateItem(TableCell.java:644)
at javafx.scene.control.TableCell.indexChanged(TableCell.java:468)
at javafx.scene.control.IndexedCell.updateIndex(IndexedCell.java:116)
at com.sun.javafx.scene.control.skin.TableRowSkinBase.updateCells(TableRowSkinBase.java:533)
at com.sun.javafx.scene.control.skin.TableRowSkinBase.init(TableRowSkinBase.java:147)
at com.sun.javafx.scene.control.skin.TableRowSkin.<init>(TableRowSkin.java:64)
at javafx.scene.control.TableRow.createDefaultSkin(TableRow.java:212)
at javafx.scene.control.Control.impl_processCSS(Control.java:872)
at javafx.scene.Node.processCSS(Node.java:9058)
at javafx.scene.Node.applyCss(Node.java:9155)
at com.sun.javafx.scene.control.skin.VirtualFlow.setCellIndex(VirtualFlow.java:1964)
at com.sun.javafx.scene.control.skin.VirtualFlow.addTrailingCells(VirtualFlow.java:1344)
at com.sun.javafx.scene.control.skin.VirtualFlow.layoutChildren(VirtualFlow.java:1197)
at javafx.scene.Parent.layout(Parent.java:1087)
at javafx.scene.Parent.layout(Parent.java:1093)
at javafx.scene.Parent.layout(Parent.java:1093)
at javafx.scene.Parent.layout(Parent.java:1093)
at javafx.scene.Parent.layout(Parent.java:1093)
at javafx.scene.Scene.doLayoutPass(Scene.java:552)
at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2397)
at com.sun.javafx.tk.Toolkit.lambda$runPulse$29(Toolkit.java:398)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:397)
at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:424)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:518)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:498)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulseFromQueue(QuantumToolkit.java:491)
at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$403(QuantumToolkit.java:319)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
at java.lang.Thread.run(Thread.java:748)
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at library.DatabaseController$4.call(DatabaseController.java:105)
at library.DatabaseController$4.call(DatabaseController.java:103)
at javafx.scene.control.TableColumn.getCellObservableValue(TableColumn.java:578)
at javafx.scene.control.TableColumn.getCellObservableValue(TableColumn.java:563)
at javafx.scene.control.TableCell.updateItem(TableCell.java:644)
at javafx.scene.control.TableCell.indexChanged(TableCell.java:468)
at javafx.scene.control.IndexedCell.updateIndex(IndexedCell.java:116)
at com.sun.javafx.scene.control.skin.TableRowSkinBase.updateCells(TableRowSkinBase.java:533)
at com.sun.javafx.scene.control.skin.TableRowSkinBase.init(TableRowSkinBase.java:147)
at com.sun.javafx.scene.control.skin.TableRowSkin.<init>(TableRowSkin.java:64)
at javafx.scene.control.TableRow.createDefaultSkin(TableRow.java:212)
at javafx.scene.control.Control.impl_processCSS(Control.java:872)
at javafx.scene.Parent.impl_processCSS(Parent.java:1280)
at javafx.scene.Parent.impl_processCSS(Parent.java:1280)
at javafx.scene.Parent.impl_processCSS(Parent.java:1280)
at javafx.scene.Parent.impl_processCSS(Parent.java:1280)
at javafx.scene.control.Control.impl_processCSS(Control.java:868)
at javafx.scene.Node.processCSS(Node.java:9058)
at javafx.scene.Node.processCSS(Node.java:9051)
at javafx.scene.Node.processCSS(Node.java:9051)
at javafx.scene.Node.processCSS(Node.java:9051)
at javafx.scene.Scene.doCSSPass(Scene.java:545)
at javafx.scene.Scene.access$3600(Scene.java:159)
at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2392)
at com.sun.javafx.tk.Toolkit.lambda$runPulse$29(Toolkit.java:398)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:397)
at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:424)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:518)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:498)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulseFromQueue(QuantumToolkit.java:491)
at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$403(QuantumToolkit.java:319)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
at java.lang.Thread.run(Thread.java:748)

```