import java.awt.datatransfer.*;
import java.awt.Toolkit;

String myString = "This text will be copied into clipboard when running this code!";
StringSelection stringSelection = new StringSelection(myString);
Clipboard clpbrd = Toolkit.getDefaultToolkit().getSystemClipboard();
clpbrd.setContents(stringSelection, null);

import java.awt.AWTException;
import java.awt.HeadlessException;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.event.KeyEvent;
import java.io.IOException;

public class SystemClipboard
{
    public static void copy(String text)
    {
        Clipboard clipboard = getSystemClipboard();

        clipboard.setContents(new StringSelection(text), null);
    }

    public static void paste() throws AWTException
    {
        Robot robot = new Robot();

        robot.keyPress(KeyEvent.VK_CONTROL);
        robot.keyPress(KeyEvent.VK_V);
        robot.keyRelease(KeyEvent.VK_CONTROL);
        robot.keyRelease(KeyEvent.VK_V);
    }

    public static String get() throws Exception
    {
        Clipboard systemClipboard = getSystemClipboard();
        DataFlavor dataFlavor = DataFlavor.stringFlavor;

        if (systemClipboard.isDataFlavorAvailable(dataFlavor))
        {
            Object text = systemClipboard.getData(dataFlavor);
            return (String) text;
        }

        return null;
    }

    private static Clipboard getSystemClipboard()
    {
        Toolkit defaultToolkit = Toolkit.getDefaultToolkit();
        Clipboard systemClipboard = defaultToolkit.getSystemClipboard();

        return systemClipboard;
    }
}

Toolkit.getDefaultToolkit()
                .getSystemClipboard()
                .setContents(
                        new StringSelection(txtMySQLScript.getText()),
                        null
                );