FULL PRODUCT VERSION :
OpenJDK 1.6.0_20

ADDITIONAL OS VERSION INFORMATION :
Ubuntu 32 bit, Kubuntu 32 bit

A DESCRIPTION OF THE PROBLEM :
If fractional metrics are enabled the subpixel text antialiasing draws illegal color lines. For HRGB for example, it draws vertical shadows in incorrect coordinates.
See this screenshot:
http://magicplot.com/openjdk-aa-bug.png

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
You can use this little text app to see this bug:
http://magicplot.com/MPTextTest.jar
http://magicplot.com/MagicPlotTextTest.java
Select one of LCD_ antialiasing modes.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Text antialiasing must work like when fractional metrics are off.
ACTUAL -
Incorrect colored lines are drawn. The text is damaged in fact.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
  To set appropriate text rendering options use these methods before invocation gr.drawString(...):

Graphics2D gr = ...
gr.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB);
gr.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Do not use fractional metrics if possible. If fractional metrics are required simple 'gray' antialiasing can be used (TEXT_ANTIALIASING_ON redering hint).