FULL PRODUCT VERSION :
java version "1.6.0_25"
Java(TM) SE Runtime Environment (build 1.6.0_25-b06)
Java HotSpot(TM) 64-Bit Server VM (build 20.0-b11, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
A certain example of Unicode on the web had an example of how the zero width joiner can actually make a semantic difference. I constructed a test in Java to see what would happen, and the result was failure to render the text correctly.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the attached example.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The joiner should be handled, so the whole thing should appear as a single stacked character.
ACTUAL -
The two halves split, rendering incorrectly.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.swing.JOptionPane;

public class Test
{
    public static void main(String[] args) throws Exception
    {
        String string = "\u0DC1\u0DCA\u200D\u0dbb\u0dd3";
        JOptionPane.showMessageDialog(null, string);
    }
}

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