FULL PRODUCT VERSION :
JDK 1.6_0_02

ADDITIONAL OS VERSION INFORMATION :
Win XP SP2

A DESCRIPTION OF THE PROBLEM :
  Justification sometimes leaves a blank space at the end of justified lines; noticeable when inserting characters in of a paragraph.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Reproducible. Modify jfc/demoSylepad:

Stylepad.properties, modify:
toolbar=... bullets
[just use spare icon already there]

Stylepad.java, add in defaultActions:
            new StyledEditorKit.AlignmentAction("bullets",
StyleConstants.ALIGN_JUSTIFIED),

Run stylepad.jar.
In paragraph "This was not an encouraging...", press bullets button, paragraph is justified ok.
At the begining of paragraph insert string:
"a a a a a a a a a a a a ".

First line ends with period folowed by a space. Similarly, inserting text in paragraphs sometimes makes lines end with other character and a space.



REPRODUCIBILITY :
This bug can be reproduced always.