Copying to the clipboard in Java [duplicate]

Use the Toolkit to get the system clipboard. Create a StringSelection with the String and add it to the Clipboard.

Simplified:

StringSelection selection = new StringSelection(theString);
Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
clipboard.setContents(selection, selection);

Here is a simple SSCCE to accomplish this:

import java.awt.*;
import java.awt.datatransfer.*;
import java.io.*;

class ClipboardTest
{
    public static void main(String[] args)
        throws UnsupportedFlavorException, IOException
    {
        Clipboard c = Toolkit.getDefaultToolkit().getSystemClipboard();
        StringSelection testData;

        //  Add some test data

        if (args.length > 0)
            testData = new StringSelection( args[0] );
        else
            testData = new StringSelection( "Test Data" );

        c.setContents(testData, testData);

        //  Get clipboard contents, as a String

        Transferable t = c.getContents( null );

        if ( t.isDataFlavorSupported(DataFlavor.stringFlavor) )
        {
            Object o = t.getTransferData( DataFlavor.stringFlavor );
            String data = (String)t.getTransferData( DataFlavor.stringFlavor );
            System.out.println( "Clipboard contents: " + data );
        }

        System.exit(0);
    }
}

For anyone still stumbling upon this post searching for the JavaFX way to accomplish this, here you go:

ClipboardContent content = new ClipboardContent();
content.putString("Some text");
content.putHtml("<b>Bold</b> text");
Clipboard.getSystemClipboard().setContent(content);

For further information, read the documentation.

If you are on Linux and using OpenJDK, it will not work. You must use the Sun JDK on Linux for it to work.