FULL PRODUCT VERSION :
[problematic version]
java version "1.6.0_0"
OpenJDK Runtime Environment (IcedTea6 1.6) (fedora-33.b16.fc12-x86_64)
OpenJDK 64-Bit Server VM (build 14.0-b16, mixed mode)

[working version]


ADDITIONAL OS VERSION INFORMATION :
Linux 2.6.31.12-174.2.3.fc12.x86_64 #1 SMP Mon Jan 18 19:52:07 UTC 2010 x86_64 x86_64 x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
java version "1.6.0_15"
Java(TM) SE Runtime Environment (build 1.6.0_15-b03)
Java HotSpot(TM) 64-Bit Server VM (build 14.1-b02, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the attached test case under Sun java and OpenJDK it will report the time taken to run the drawing routine. Without anti-aliasing the results are very similar, but with aa enabled the OpenJDK is around 20X slower than the sun java.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Similar performance under anti-aliasing from Sun Java and OpenJDK
ACTUAL -
  From the openJDK with AA 10 refreshes take ~14000ms.

  From the openJDK without AA 10 refreshes take ~300ms

  From the Sun JRE with AA 10 refreshes take ~750ms

  From the Sun JRE without AA 10 refreshes take ~300ms

On the antialiased results the openJDK is about 20X slower than the sun JRE.


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.util.Date;

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


public class SlowDrawApplication extends JFrame {


public SlowDrawApplication () {
setContentPane(new SlowDrawPanel());
setSize(800,800);
setLocationRelativeTo(null);
setVisible(true);
}

public static void main(String[] args) {
new SlowDrawApplication();
}


private class SlowDrawPanel extends JPanel {

private int redrawCount = 0;
private long startTime = (new Date()).getTime();
private long endTime;


public void paint (Graphics g) {
super.paint(g);

// Comment out this line to remove anti-aliasing
((Graphics2D)g).setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

if (redrawCount == 10) {
endTime = (new Date()).getTime();
}
if (redrawCount > 10) {
g.drawString("Finished in "+(endTime-startTime)+"ms", getWidth()/2, getHeight()/2);
return;
}

++redrawCount;

// Do lots of angled lines

for (int x=10;x<getWidth();x+=10) {
for (int y=10;y<getHeight();y+=10) {
g.drawLine(x, y, x-10, y-10);
}
}

repaint();
}
}
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Disabling anti-aliasing.