Java clipboard not working - linux

Question

I was trying to copy an image to the clipboard and paste it into gimp with this code snippet:
BufferedImage bi = new BufferedImage(board.getAmount()*16,16,BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = bi.createGraphics();
Color[] colors = board.getColors();
for (int loop = 0; loop < board.getAmount(); loop++) {
g2d.setColor(colors[loop]);
g2d.fill(new Rectangle(16*loop,0,16,16));
}
ImageSelection is = new ImageSelection(bi);
Toolkit.getDefaultToolkit().getSystemClipboard().setContents(is, null);
Anyways in theory everything should have worked out fine. It gave me no errors, but when I try to paste the image, nothing happens.
This was done on two different linux machines and neither worked. I then came to school and tried it out with the same code on Windows and it worked.
So I guess my real question is does it have something to do with open-jdk, or java 1.7, or is it linux's problem? And how can I fix it?

Answer 1

I think the next page could be useful: http://www.java2s.com/Code/Java/2D-Graphics-GUI/SendingImageObjectsthroughtheClipboard.htm.
Consider the following lines to copy the image to the clipboard.
final Clipboard clipboard = frame.getToolkit().getSystemClipboard();
label.setTransferHandler(new ImageSelection());
...
TransferHandler handler = label.getTransferHandler();
handler.exportToClipboard(label, clipboard, TransferHandler.COPY);

Answer 2

I had the same problem, and found this to work:
final Clipboard clipboard = frame.getToolkit().getSystemSelection();
...then continue using that as a regular clipboard. The "system selection" allows you to change what the window manager thinks is selected, and is therefore "on the clipboard".
I'm not sure what the best way to detect whether system selection or system clipboard should be used, but it looks like Windows will return null for getSystemSelection, so that can be used as a test.