The use case is to be able to reset the font that would have been set on a TextField/TextArea thanks to CSS.
The general algorithm that is applied in this case is to:
- Create the initialValue thanks to StyleableProperty
- call textInputSkin.impl_cssSet(property, value);

In the case of a Font, there is no initialValue and the Skin doesn't react well when null value is provided.

WARNING: javafx.scene.Node impl_cssSet Failed to set css [StyleableProperty {owningClass: com.sun.javafx.scene.control.skin.TextInputControlSkin, fieldName: font, property: -fx-font, converter: FontConverter, initialValue: '', inherits: true, subProperties: ['artificial' StyleableProperty {property: -fx-font-family, converter: StringConverter, initialValue: null}, 'artificial' StyleableProperty {property: -fx-font-size, converter: SizeConverter, initialValue: null}, 'artificial' StyleableProperty {property: -fx-font-weight, converter: Font.WeightConverter, initialValue: null}, 'artificial' StyleableProperty {property: -fx-font-style, converter: Font.StyleConverter, initialValue: null}]}]

java.lang.NullPointerException
at com.sun.javafx.scene.control.skin.TextFieldSkin$12.computeValue(TextFieldSkin.java:224)
at javafx.beans.binding.DoubleBinding.get(DoubleBinding.java:182)
at javafx.beans.binding.DoubleExpression.doubleValue(DoubleExpression.java:42)
at javafx.beans.property.DoublePropertyBase.get(DoublePropertyBase.java:109)
at javafx.scene.text.Text.getY(Text.java:237)
at javafx.scene.text.Text.updatePGText(Text.java:1288)
at javafx.scene.text.Text.impl_updatePG(Text.java:1330)
at javafx.scene.Node.impl_syncPGNodeDirect(Node.java:413)
at com.sun.javafx.tk.quantum.PrismTextHelper.getCaretShape(PrismTextHelper.java:43)
at javafx.scene.text.Text.getDecorationShapes(Text.java:1012)
at javafx.scene.text.Text.impl_geomChanged(Text.java:637)
at javafx.scene.text.Text$3.invalidated(Text.java:247)
at javafx.beans.property.DoublePropertyBase.markInvalid(DoublePropertyBase.java:88)
at javafx.beans.property.DoublePropertyBase.access$100(DoublePropertyBase.java:28)
at javafx.beans.property.DoublePropertyBase$Listener.invalidated(DoublePropertyBase.java:210)
at com.sun.javafx.binding.ExpressionHelper$SingleInvalidation.fireValueChangedEvent(ExpressionHelper.java:140)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:64)
at javafx.beans.binding.DoubleBinding.invalidate(DoubleBinding.java:201)
at com.sun.javafx.binding.BindingHelperObserver.invalidated(BindingHelperObserver.java:29)
at com.sun.javafx.binding.ExpressionHelper$SingleInvalidation.fireValueChangedEvent(ExpressionHelper.java:140)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:64)
at javafx.beans.binding.ObjectBinding.invalidate(ObjectBinding.java:150)
at com.sun.javafx.binding.BindingHelperObserver.invalidated(BindingHelperObserver.java:29)
at com.sun.javafx.binding.ExpressionHelper$MultipleInvalidation.fireValueChangedEvent(ExpressionHelper.java:301)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:64)
at javafx.beans.property.ObjectPropertyBase.fireValueChangedEvent(ObjectPropertyBase.java:82)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:89)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:122)
at com.sun.javafx.scene.control.skin.TextInputControlSkin.impl_cssSet(TextInputControlSkin.java:400)
at javafx.scene.Node.impl_cssSet(Node.java:6347)
at com.oracle.javafx.authoring.Deprecation.impl_cssSet(Deprecation.java:47)
at com.oracle.javafx.authoring.css.CssUtils.resetStyle(CssUtils.java:143)
at com.oracle.javafx.authoring.css.CssUtils.resetStyle(CssUtils.java:410)
at com.oracle.javafx.authoring.css.CssUtils.resetCssState(CssUtils.java:400)
at com.oracle.javafx.authoring.css.CssUtils.applyCss(CssUtils.java:465)
at com.oracle.javafx.authoring.runtime.ComponentState.applyStateValuesRecursively(ComponentState.java:112)
at com.oracle.javafx.authoring.runtime.ComponentState.refreshState(ComponentState.java:101)
at com.oracle.javafx.authoring.runtime.ElementStates$StateTransactionListener.unknownChanges(ElementStates.java:516)
at com.oracle.javafx.authoring.model.transactions.TransactionManager.notifyUnknownChanges(TransactionManager.java:122)
at com.oracle.javafx.authoring.model.transactions.Transaction.close(Transaction.java:156)
at com.oracle.javafx.authoring.stage.v2.DropOperation.positionChildrenInNextTick(DropOperation.java:180)
at com.oracle.javafx.authoring.stage.v2.DropOperation$1$1.run(DropOperation.java:149)
at com.sun.javafx.application.PlatformImpl$3.run(PlatformImpl.java:108)