Painting and updating:

The paint () function is called every time your applet's output must be redrawn. This condition can occur for various reasons. For instance, the window in which the applet is running might be overwritten through another window and then uncovered, or the applet window might be minimized and then restored. A Paint() is also called whenever the applet starts execution. Whatever the cause, whenever the applet have to redraw its output, paint() method is called. A paint() method has one parameter of type Graphics. This parameter will holds the graphics context, that describes the graphics environment in that the applet is running. That context is used whenever output to the applet is needed.

Method paint is used to paint or repaint the screen. It is automatically called through repaint or could be called explicitly through the applet. An applet calls paint whenever the browser needs a   repaint, like as when an obscured applet   is brought to the front of the screen again.

Paint method has a fixed format. That always must be named paint have a return type of void and be declared public. Therefore, unlike init and begin, it does have an argument, of type graphics. This is a predefined type in java which contains several of the methods for writing graphics to the screen. Here is an instance of a paint method:

public void paint(Graphics g) {

g.drawstring("counter = " + counter, 10,10);

}

That method writes the value of counter to the screen every time it is invoked. Combine this along with begin and repaint methods. A start method increments counter and then calls repaint. The screen shows the new value of counter every time it is updated. A compiler does not need a paint method. It overrides a default method provided through java.applet.Applet. Then, you do not be able to write anything to the screen.

After you have initialized the spreadsheet, you have to display it. This is commonly done through means of the apit b( ) method, that draw all the objects added during the initialization phase. As describe in "Step 4. Sizing spreadsheet, the object should sized according to the dimensions of the frame or a key constraint like as the font size. You should also paint the objects in the sequence they are to be added to the frame.