public class Screenshot
{

public static void main(String[] args) throws Exception
{
// make sure we have exactly two arguments,
// a waiting period and a file name
if (args.length != 2)
{
System.err.println("Usage: java Screenshot " +
"WAITSECONDS OUTFILE.png");
System.exit(1);
}
// check if file name is valid
String outFileName = args[1];
if (!outFileName.toLowerCase().endsWith(".png"))
{
System.err.println("Error: output file name must " +
"end with ".png".");
System.exit(1);
}
// wait for a user-specified time
try
{
long time = Long.parseLong(args[0]) * 1000L;
System.out.println("Waiting " + (time / 1000L) +
" second(s)...");
Thread.sleep(time);
}
catch(NumberFormatException nfe)
{
System.err.println(args[0] + " does not seem to be a " +
"valid number of seconds.");
System.exit(1);
}
// determine current screen size
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension screenSize = toolkit.getScreenSize();
Rectangle screenRect = new Rectangle(screenSize);
// create screen shot
Robot robot = new Robot();
BufferedImage image = robot.createScreenCapture(screenRect);
// save captured image to PNG file
ImageIO.write(image, "png", new File(outFileName));
// give feedback
System.out.println("Saved screen shot (" + image.getWidth() +
" x " + image.getHeight() + " pixels) to file "" +
outFileName + "".");

}
}