import javafx.beans.property.DoubleProperty; import javafx.beans.property.SimpleDoubleProperty; public class Konto { private DoubleProperty stand; public final double getStand() { if (stand != null) return stand.get(); return 0; } public final void setStand(double hoehe) { this.standProperty().set(hoehe); } public final DoubleProperty standProperty() { if (stand == null) { stand = new SimpleDoubleProperty(0); } return stand; } }