I'm having a lot of questions about Java graphical libraries, which are as follows:
What is the difference between overwriting the paint(Graphics) method or the paintComponent(Graphics) method?
What is the Graphics2D class of difference in relation to class Graphics ?
The paint(Graphics) method in lightweight components (those of Swing) accomplishes these three things, in that order:
Paints the contents of the component itself by calling the paintComponent(Graphics) method.
Paints the subcomponents when calling the paintChildren(Graphics) method.
Paints the edge of the component when calling the paintBorder(Graphics) method.
The paint(Graphics) method also does a few more things to determine which area is to be painted. It also handles the case that you are printing the component (to the printer), then calling the print*(Graphics) methods instead of paint*(Graphics) . See it all in matching source code .
As you will hardly want to change this default functioning of paint(Graphics) % (there is little reason to do so), hardly would override such a method is meaningless. Therefore, override the paintComponent(Graphics) method that actually draws the component.
The class Graphics2D is a subclass of Graphics . It has many more methods, just take a quick look at javadoc it
