Description Anthony Hunter 2006-10-10 16:56:33 EDT

java.lang.NullPointerException
  at org.eclipse.gmf.runtime.draw2d.ui.internal.graphics.PrinterGraphics.dispose(PrinterGraphics.java:73)
  at org.eclipse.gmf.runtime.diagram.ui.printing.internal.util.DiagramPrinter.dispose(DiagramPrinter.java:533)
  at org.eclipse.gmf.runtime.diagram.ui.printing.internal.util.DiagramPrinter.run(DiagramPrinter.java:213)
  at org.eclipse.gmf.runtime.diagram.ui.printing.util.DiagramPrinterUtil.printDiagrams(DiagramPrinterUtil.java:66)
etc....

you won't see an exception in the log, but the exception does occur.

The problem can contribute to a SWT handle leak. In org.eclipse.gmf.runtime.draw2d.ui.internal.graphics.PrinterGraphics#dispose the code tries to dispose all the images in collapseImageCache, but if any are already disposed there hashCode has changed and HashMap#get will return null. A better approach is to iterate over the values which will never be null. An image can safely be disposed twice. The suggested code below is similar to that found in the base class.

	public void dispose() {

		for (Iterator it = collapseImageCache.values().iterator(); it.hasNext();) {
			Image img = (Image) it.next();
			img.dispose();
		}

		collapseImageCache.clear();

		super.dispose();
	}