Use code to reproduce:


import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.ButtonBuilder;
import javafx.scene.input.Clipboard;
import javafx.scene.input.ClipboardContent;
import javafx.scene.input.DataFormat;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class SimpleApp extends Application {

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

    @Override
    public void start(Stage stage) throws Exception {
        VBox rbox = new VBox(10);

        final ClipboardContent content = new ClipboardContent();

        rbox.getChildren().add(ButtonBuilder.create().text("Put to clipboard").onAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent t) {
                content.put(DataFormat.URL, CONTENT_URL);
                Clipboard.getSystemClipboard().setContent(content);
            }
        }).build());

        rbox.getChildren().add(ButtonBuilder.create().text("paste from clipboard").onAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent t) {
                System.out.println("URL : " + Clipboard.getSystemClipboard().getContent(DataFormat.URL));
                System.out.println("FILE : " + Clipboard.getSystemClipboard().getContent(DataFormat.FILES));
            }
        }).build());

        Scene scene = new Scene(rbox, 300, 300);
        stage.setScene(scene);
        stage.show();
    }
    final static String CONTENT_URL = "http://www.oracle.com";
}

Put to clipboard and get from it.
I see output:
run:
URL : http://www.oracle.com
FILE : [http:/www.oracle.com]