Below is a full, short code example.  I purposely used angles of 90 and
180, which seemed like the simplest case.

There seems to be a one pixel discrepancy between the fill and the
drawn line that extends roughly through the lower right quadrant.

Image of the problem: http://www.bounceswoosh.org/misc/pie.png

Is there something I should be doing differently in order to get the
line to exactly match the edge of the fill?

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class SimpleArcTest extends JPanel
{
   protected int angles[] = {90, 90, 180};
   protected Color colors[] = {Color.BLUE, Color.MAGENTA, Color.DARK_GRAY};
   
   public static void main(String[] args)
   {
       JFrame frame = new JFrame();
       JPanel panel = new SimpleArcTest();
       panel.setBackground(Color.WHITE);
       
       panel.setPreferredSize(new Dimension(400,400));
       
       frame.getContentPane().add(panel);
       
       frame.pack();
       frame.setVisible(true);
   }
   
   protected void paintComponent(Graphics g)
   {
       super.paintComponent(g);
       
       int startAngle = 0;
       
       for (int i = 0; i < angles.length; i++)
       {
           g.setColor(colors[i]);
           g.fillArc(getX(), getY(), getWidth(), getHeight(),
                   startAngle, angles[i]);
           
           g.setColor(Color.BLACK);
           g.drawArc(getX(), getY(), getWidth(), getHeight(),
                   startAngle, angles[i]);
           
           startAngle += angles[i];
       }
   }
}