FULL PRODUCT VERSION :
java version "1.5.0_02"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_02-b09)
Java HotSpot(TM) Client VM (build 1.5.0_02-b09, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

EXTRA RELEVANT SYSTEM CONFIGURATION :
Problem occurs also on WIN2000SP4 on several different PCs

A DESCRIPTION OF THE PROBLEM :
The jps and the jconsole commands do not work when using them on a user name that contains an underscore '_'.
An easy test to see the problem is to run the jps command (see below).
When using a user without underscore using the same java program to investigate, no problem occurs.
The Problem occurs not only on XP but also under Win2000.
I tried in on several PCs and always the same result: The underscore in the user name was the reason for the problem.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
- just create a user that contains an underscore '_' in its name
- start any java application
- use jps -vl
- result:
C:\Program Files\Java\jdk1.5.0_02\bin>jps -vl
3660 sun.tools.jps.Jps -Dapplication.home=C:\SimProgs\Java\jdk1.5.0_02 -Xms8m
1272 -- process information unavailable

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
the name of the appliation should be displayed

here's the result using the same tools, but a user name without '_'
D:\Documents and Settings\li64875>jps -vl
3660 sun.tools.jps.Jps -Dapplication.home=C:\SimProgs\Java\jdk1.5.0_02 -Xms8m
1272 NameServer0.1.jar

ACTUAL -
result is: process information unavailable

C:\Program Files\Java\jdk1.5.0_02\bin>jps -vl
3660 sun.tools.jps.Jps -Dapplication.home=C:\SimProgs\Java\jdk1.5.0_02 -Xms8m
1272 -- process information unavailable

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
changing the user name.
But this name is used on about 60 PCs for auto login and
for a samba share and has to be modified by our centralized  IT service