Java - Drag and Drop

import java.awt.Color;
import java.awt.Component;
import java.awt.Desktop;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetDragEvent;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.dnd.DropTargetEvent;
import java.awt.dnd.DropTargetListener;
import java.io.File;
import java.util.ArrayList;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SpringLayout;
import javax.swing.SwingConstants;
import javax.swing.border.LineBorder;

/**
 * @author Stefan, https://st-page.de
 *
 */
public class DragAndDrop extends JFrame
{

    private static final long serialVersionUID = 1L;

    public DragAndDrop()
    {
        setSize(new Dimension(691, 363));
        setPreferredSize(new Dimension(300, 200));
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setTitle("Java Drag And Drop");
    SpringLayout springLayout = new SpringLayout();
    getContentPane().setLayout(springLayout);

    JLabel lblDraganddrop = new JLabel("Drag And Drop");
    springLayout.putConstraint(SpringLayout.NORTH, lblDraganddrop, 10, SpringLayout.NORTH, getContentPane());
    springLayout.putConstraint(SpringLayout.WEST, lblDraganddrop, 10, SpringLayout.WEST, getContentPane());
    springLayout.putConstraint(SpringLayout.SOUTH, lblDraganddrop, 315, SpringLayout.NORTH, getContentPane());
    springLayout.putConstraint(SpringLayout.EAST, lblDraganddrop, -10, SpringLayout.EAST, getContentPane());
    lblDraganddrop.setHorizontalTextPosition(SwingConstants.CENTER);
    lblDraganddrop.setHorizontalAlignment(SwingConstants.CENTER);
    lblDraganddrop.setBorder(new LineBorder(new Color(0, 0, 0)));
    lblDraganddrop.setAlignmentX(Component.CENTER_ALIGNMENT);
    lblDraganddrop.setVerticalAlignment(SwingConstants.CENTER);
    lblDraganddrop.setVerticalTextPosition(SwingConstants.CENTER);
    lblDraganddrop.setFont(new Font("Tahoma", Font.PLAIN, 48));
    getContentPane().add(lblDraganddrop);

    setVisible(true);

    new DropTarget(lblDraganddrop, new DropTargetListener()
    {
        @Override
        public void drop(DropTargetDropEvent dtde)
        {
        try
        {
            Transferable tr = dtde.getTransferable();
            DataFlavor[] flavors = tr.getTransferDataFlavors();
            ArrayList<File> fileNames = new ArrayList<File>();
            for (int i = 0; i < flavors.length; i++)
            {
            if (flavors[i].isFlavorJavaFileListType())
            {
                dtde.acceptDrop(dtde.getDropAction());
                @SuppressWarnings("unchecked")
                java.util.List<File> files = (java.util.List<File>) tr.getTransferData(flavors[i]);
                for (int k = 0; k < files.size(); k++)
                {
                fileNames.add(files.get(k));
                // Die Dateien werden mit dem spezifischen Programm geöffnet.
                Desktop.getDesktop().open(files.get(k));
                // Der Dateiname wird in der Comandozeile ausgegeben.
                System.out.println(files.get(k));
                }

                dtde.dropComplete(true);
            }
            }
            return;
        }
        catch (Throwable t)
        {
            t.printStackTrace();
        }
        dtde.rejectDrop();

        }

        @Override
        public void dragEnter(DropTargetDragEvent dtde)
        {}

        @Override
        public void dragOver(DropTargetDragEvent dtde)
        {}

        @Override
        public void dropActionChanged(DropTargetDragEvent dtde)
        {}

        @Override
        public void dragExit(DropTargetEvent dte)
        {}

    });
    }

    /**
     * Hier wird das Programm ohne weitere Argumente gestartet.
     * @param args
     */
    public static void main(String[] args)
    {
    new DragAndDrop();
    }
}