How to save animation as a file (“Alogorithms 4th Edition” by Robert Sedgewick and Kevin Wayne.)

I am reading “Algorithms 4th Edition” by Robert Sedgewick and Kevin Wayne.
Using StdDraw, we can create animation:

package general_test;  import edu.princeton.cs.algs4.StdDraw;  public class AnimationTest {      public static void main(String[] args) {         // TODO Auto-generated method stub        StdDraw.setScale(-2, +2);        StdDraw.enableDoubleBuffering();         for (double t = 0.0; true; t += 0.02) {            double x = Math.sin(t);            double y = Math.cos(t);            StdDraw.clear();            StdDraw.filledCircle(x, y, 0.05);            StdDraw.filledCircle(-x, -y, 0.05);            StdDraw.show();            StdDraw.pause(20);        }     }  } 

I want to save this animation as a file.
How can I save this animation as a file?
Any easy way?