learning java AWT 剪贴板 传递文本

import javax.swing.*;
import java.awt.*;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;

public class SimpleCliboard {
    private Frame f = new Frame("test");
    private Clipboard clipboard =  Toolkit.getDefaultToolkit().getSystemClipboard();

    private TextArea jtaCopyTo = new TextArea(5,20);
    private TextArea jtaPaste = new TextArea(5,20);
    private Button btCopy = new Button("copy");
    private Button btPaste = new Button("paste");

    public void init(){
        var p = new Panel();
        p.add(btCopy);
        p.add(btPaste);
        btCopy.addActionListener(e -> {
            var contents = new StringSelection(jtaCopyTo.getText());
            clipboard.setContents(contents,null);
        });

        btPaste.addActionListener(e -> {
            if (clipboard.isDataFlavorAvailable(DataFlavor.stringFlavor)){
                try {
                    var content = (String) clipboard.getData(DataFlavor.stringFlavor);
                    jtaPaste.append(content);
                } catch (UnsupportedFlavorException ex) {
                    ex.printStackTrace();
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            }
        });

        var box = new Box(BoxLayout.X_AXIS);
        box.add(jtaCopyTo);
        box.add(jtaPaste);

        f.add(p,BorderLayout.SOUTH);
        f.add(box,BorderLayout.CENTER);
        f.pack();
        f.setVisible(true);
    }

    public static void main(String[] args) {
        new SimpleCliboard().init();
    }
}