Java SE (Java Platform, Standard Edition)

anyone?  I'm struggling with the same issue...  Not trying to be lazy... 

Is your model using a java.util.Date? If so the simplest thing would be to update the model classes so they use the new java.time API. You should consider the old Date and Calendar classes "nearly deprecated", imho.

If that's not possible, you'll need to do some wiring. A fairly ugly hack would be to define a StringProperty containing some string that uniquely determined your date (e.g., I suppose you could use a String representation of the number of milliseconds since epoch), then bi-directionally bind both your ObjectProperty<Date> and your DatePicker's value property to that String property, using appropriate StringConverters in each case.

Or, just use a couple of listeners and update each property when the other changes. Here's an example if you need this approach:

import java.text.DateFormat;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.temporal.ChronoField;
import java.util.Date;


import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.DatePicker;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;




public class Main extends Application {
  @Override
  public void start(Stage primaryStage) {
  BorderPane root = new BorderPane();

  ObjectProperty<Date> date = new SimpleObjectProperty<>(new Date());

  DatePicker datePicker = new DatePicker(LocalDate.now());
  Button addDayButton = new Button("Add day");
  addDayButton.setOnAction(event -> date.set(new Date(date.get().getTime() + 24 * 60 * 60 * 1000)));
  Button subtractDayButton = new Button("Subtract day");
  subtractDayButton.setOnAction(event -> date.set(new Date(date.get().getTime() - 24 * 60 * 60 * 1000)));

  Label label = new Label();
  DateFormat format = DateFormat.getDateInstance();
  label.textProperty().bind(Bindings.createStringBinding(() -> format.format(date.get()), date));

  date.addListener((obs, oldDate, newDate) -> {  
     
  Instant instant = newDate.toInstant();
  ZonedDateTime zonedDateTime = ZonedDateTime.ofInstant(instant, ZoneId.systemDefault());
  LocalDate localDate = zonedDateTime.toLocalDate();
     if ( ! datePicker.getValue().equals(localDate)) {  
        datePicker.setValue(localDate);  
     }  
  });  
  datePicker.valueProperty().addListener((obs, oldDate, newDate) -> {  
  ZonedDateTime zonedDateTime = newDate.atStartOfDay(ZoneId.systemDefault());
  Instant instant = Instant.from(zonedDateTime);
  Date dateToSet = Date.from(instant);
  if (! dateToSet.equals(date.get())) {
  date.set(dateToSet);
  }
  });  

  root.setCenter(datePicker);
  HBox controls = new HBox(5, subtractDayButton, addDayButton, label);
  controls.setPadding(new Insets(10));
  controls.setAlignment(Pos.CENTER);
  root.setBottom(controls);

  Scene scene = new Scene(root,400,400);
  primaryStage.setScene(scene);
  primaryStage.show();
  }

  public static void main(String[] args) {
  launch(args);
  }
}

The conversions between Date and LocalDate are a bit tricky as they're very different beasts. Date includes a time (of day) and (sort of, implicitly) time zone information.

Thank you.  I'll give that a try later today.  I just wanted to make sure I wasn't missing something obvious.

I was lazy and changed it to LocalDate.... works.  I think I have the option to switch over my POJOs.  Thanks again for the help.

Actually much the better approach if you can do it. I updated the code to something that actually works, in case anyone else was looking at this.