When using binding with a StringExpression from an ObjectProperty an null pointer exception appears when the ObjectProperty value is set to null.

Caused by: java.lang.NullPointerException
at com.sun.javafx.binding.StringFormatter$1.computeValue(StringFormatter.java:53)
at javafx.beans.binding.StringBinding.get(StringBinding.java:107)
at javafx.beans.binding.StringBinding.get(StringBinding.java:38)
at javafx.beans.binding.ObjectExpression.getValue(ObjectExpression.java:25)
at javafx.beans.value.ObservableValueBase$ChangeListenerWrapper.invalidated(ObservableValueBase.java:127)
at javafx.beans.value.ObservableValueBase.fireValueChangedEvent(ObservableValueBase.java:107)
at javafx.beans.binding.StringBinding.invalidate(StringBinding.java:124)
at com.sun.javafx.binding.BindingHelperObserver.invalidated(BindingHelperObserver.java:26)
at javafx.beans.value.ObservableValueBase.fireValueChangedEvent(ObservableValueBase.java:107)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:57)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:107)
at javafxsamples.BidingTest.testStringExpression(BidingTest.java:34)
at javafxsamples.BidingTest.start(BidingTest.java:19)
at com.sun.javafx.application.LauncherImpl$3.run(LauncherImpl.java:127)
at com.sun.javafx.application.PlatformImpl$3.run(PlatformImpl.java:87)
at com.sun.javafx.application.PlatformImpl$2.run(PlatformImpl.java:65)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication$1$1.run(WinApplication.java:49)
... 1 more

It's a limitation of using binding, for example when we want to bind a Label with the selected Object of a ListView.

The StringFormatter should handle null value.