gistfile1.java

 private StringBinding nameBinding = new FXStringBinding() {
        @Override
        protected void configure() {
            try {
                addObservable(aProperty);
                addObservable(aProperty.get().bProperty());
                addObservable(aProperty.get().bProperty().get().cProperty());
                addObservable(aProperty.get().bProperty().get().cProperty().get().stringProperty());
            } catch (NullPointerException ignored) {
            }
        }
        @Override
        protected String compute() {
            try {
                return aProperty.get().bProperty().get().cProperty().get().stringProperty().get();
            } catch (NullPointerException e) {
                return null;
            }
        }