Found when doing 1.6.0_12-b02 PIT testing.

to reproduce:

I installed the 6u12 32 bit JDK on a 64 bit OS system silently.

Then I installed the 6u12 32 bit JRE on the same 64 bit system.

when I uninstalled the JDK (leaving the JRE intact) the uninstall did not
fully remove the JDK files.  I was left with:

C:/progra~2/Java/jdk1.6.0_12/jre.msi
C:/progra~2/Java/jdk1.6.0_12/jre1041.MST
C:/progra~2/Java/jdk1.6.0_12/jre2052.MST

My steps:

jdk160.exe /s /qn
jre160.exe /s /qn
msiexec /x "{32A3A4F4-B792-11D6-A78A-00B0D0160120}" /qb

this was via automation but I was able to reproduce by hand using the same
steps.