FULL PRODUCT VERSION :
java version "1.6.0_23"
Java(TM) SE Runtime Environment (build 1.6.0_23-b05)
Java HotSpot(TM) Client VM (build 19.0-b09, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7600]

A DESCRIPTION OF THE PROBLEM :
The jps output is wrong on Windows. It cuts away the drive letter and everything trailing a blank in the path.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Start CMD.exe, enter the following:

C:\>"C:\Program Files\Java\jdk1.6.0_23\demo\jfc\Metalworks\Metalworks.jar"
C:\>"D:\Program Files\Java\jdk1.6.0_23\demo\jfc\Metalworks\Metalworks.jar"
C:\>jps


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
12345 C:\Program Files\Java\jdk1.6.0_23\demo\jfc\Metalworks\Metalworks.jar
12346 D:\Program Files\Java\jdk1.6.0_23\demo\jfc\Metalworks\Metalworks.jar
12347 Jps

ACTUAL -
Without any options given to JPS:

12345 Program
12346 Program
12347 Jps

(which is totally useless!)

With -m given:

12345 Program Files\Java\jdk1.6.0_23\demo\jfc\Metalworks\Metalworks.jar
12346 Program Files\Java\jdk1.6.0_23\demo\jfc\Metalworks\Metalworks.jar
12347 Jps

(which is missing the drive letter, an such hides the distinction between C: and D:, and such is rather useless)

With -ml given:

12345 C:\Program Files\Java\jdk1.6.0_23\demo\jfc\Metalworks\Metalworks.jar
12346 C:\Program Files\Java\jdk1.6.0_23\demo\jfc\Metalworks\Metalworks.jar
12347 sun.tools.jps.Jps -ml

Which solves the problem, but mixes up class names and JAR names.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
There is no error message provided.

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
Always provided -lm to find out the path of the executed JAR file, and ignore the fact that it mixes in class names.
Here are a couple of older bugs that discuss most of what's in this report:

5087010 4/4 jps parsing error when jar path contains embedded spaces
6456333 4/3 Incorrect jar name handle by jps in case java -jar.

One observation that appears to be new in this bug report is
the drive letter issue on Windows.