drawOval() is the method of a Graphics class.To draw a oval we use drawOval(int xaxis,int yaxis,int widthh, int heightt) method.
Graphics operations can be performed using java.awt package that contains various classes and methods for creating graphics and images.The paint() takes graphic object as an argument and provides reference to graphics drawing methods(setColor(),drawstring()).
The Runnable interface consists of a single method run() which required for implementing thread. We will create a thread and pass the object of the class that implements the Runnable interface as an argument of the Thread class’s constructor. The thread will now be activated by calling the start().
The event classes represents the events that are generated when an end user interact with the AWT components. An event is an object which specifies the change of state in the source.
A Check box is a AWT control that is used to turn an option on(true) or off(false). It consists of a small box that is either selected or unselected based on whether the Boolean argument is true or false.