javafx DragDropped file

public class EffectTest extends Application {
@Override
public void start(Stage primaryStage) {
Group root = new Group();
Scene scene = new Scene(root, 551, 400);
scene.setOnDragOver((DragEvent event) -> {
Dragboard db = event.getDragboard();
if (db.hasFiles()) {
event.acceptTransferModes(TransferMode.COPY);
} else {
event.consume();
}
});

// Dropping over surface
scene.setOnDragDropped((DragEvent event) -> {
Dragboard db = event.getDragboard();
boolean success = false;
if (db.hasFiles()) {
success = true;
String filePath = null;
for (File file:db.getFiles()) {
filePath = file.getAbsolutePath();
System.out.println(filePath);
}
}
event.setDropCompleted(success);
event.consume();
});

primaryStage.setScene(scene);
primaryStage.show();
}

}