I would "expect" that 64-bit apps would be able to run java.exe after the jre is installed (64 bit apps can spawn 32 bit ones). However that appears to not currently be the case.
I noticed that if you install the 32-bit jvm on a 64-bit OS (windows), then open (64 bit) cmd.exe
$ java -version
'java' is not recognized as an internal or external command,
operable program or batch file.
This is because instead of installing it to a directory then adding that dir to the path, the jre installer drops a java.exe it into c:\windows\system32 (which causes it, I presume, to actually be written to c:\windows\syswow64).
The path always contains c:\windows\system32
This means that 32-bit apps will "have" java.exe in their path, whereas 64-bit ones will not. I cannot imagine this is expected. Any feedback here?
64 bit windows 7
uninstall all JRE's/JDK's
make sure the uninstall worked and that the PATH environment variable is "clean" (i.e. doesn't have any java related paths in it).
Now install one JRE 64 bit.
Now open up a "64 bit" cmd.exe (for me: <windows key> + r, type in cmd.exe).
c:\> java -version
it responds with "not found"
Now open up a 32 bit app (for me, run %windir%\SysWoW64\cmd.exe)