Area.isPolygonal() has the following syntax.
public boolean isPolygonal()
In the following code shows how to use Area.isPolygonal() method.
/* w w w. ja v a 2 s . co m*/ import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.geom.AffineTransform; import java.awt.geom.Area; import java.awt.geom.Ellipse2D; import javax.swing.JFrame; import javax.swing.JPanel; public class Main extends JPanel { public void paint(Graphics g) { Graphics2D g2 = (Graphics2D) g; Ellipse2D e1 = new Ellipse2D.Double (20.0, 20.0, 80.0, 70.0); Ellipse2D e2 = new Ellipse2D.Double (20.0, 70.0, 40.0, 40.0); Area a1 = new Area (e1); Area a2 = new Area (e2); a1.subtract (a2); g2.setColor (Color.orange); g2.fill (a1); g2.setColor (Color.black); g2.drawString ("subtract", 20, 140); System.out.println(a1.isPolygonal()); } public static void main(String[] args) { JFrame frame = new JFrame(); frame.getContentPane().add(new Main()); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(200,200); frame.setVisible(true); } }