R help - Oct 2012 - Java, rJava, and Windows x64

When running [1] "R version 2.15.1 (2012-06-22)"
"x86_64-pc-mingw32",
rJava fails. I have installed both the 32-bit and 64-bit versions of 
Java 7 update 9.

 > library(rJava)
Error : .onLoad failed in loadNamespace() for 'rJava', details:
call: stop("No CurrentVersion entry in '", key, "'! Try
re-installing
Java and make sure R and Java have matching architectures.")
error: object 'key' not found
Error: package/namespace load failed for ?rJava?
 >

It appears that rJava was not seeing the x64 Java. For clarity, I 
installed the 32-bit java library second, and I imagined this might be 
the problem. The Java installer told me that it was already present, and 
the x64 library appeared to be working with the 64-bit IE9 browser

Indeed, reinstalling Java x64, the rJava package iloaded fine with the 
library(rJava) command in 64-bit R. rJava could STILL be loaded with 
library(rJava) within x86 R.

My question is, should the order of Java installation affect the ability 
of rJava to load under 64-bit R? Are there environmental variables or 
registry settings that should be checked in such cases or is it 
literally necessary to do a complete reinstall?

Rob

On Oct 29, 2012, at 11:17 AM, Robert Baer wrote:
> When running [1] "R version 2.15.1 (2012-06-22)"
"x86_64-pc-mingw32", rJava fails. I have installed both the 32-bit and
64-bit versions of Java 7 update 9.
> 
> > library(rJava)
> Error : .onLoad failed in loadNamespace() for 'rJava', details:
> call: stop("No CurrentVersion entry in '", key, "'!
Try re-installing Java and make sure R and Java have matching
architectures.")
> error: object 'key' not found
> Error: package/namespace load failed for ?rJava?
> >
> 
> It appears that rJava was not seeing the x64 Java. For clarity, I installed
the 32-bit java library second, and I imagined this might be the problem. The
Java installer told me that it was already present, and the x64 library appeared
to be working with the 64-bit IE9 browser
> 
> Indeed, reinstalling Java x64, the rJava package iloaded fine with the
library(rJava) command in 64-bit R. rJava could STILL be loaded with
library(rJava) within x86 R.
> 
> My question is, should the order of Java installation affect the ability of
rJava to load under 64-bit R? Are there environmental variables or registry
settings that should be checked in such cases or is it literally necessary to do
a complete reinstall?
> 
The registries are completely separate for 32-bit and 64-bit so installing
32-bit Java doesn't affect 64-bit R and vice-versa. rJava is simply checking
the registry that is has access to and it is the one corresponding to the R
process (so 32-bit R will check 32-bit registry and 64-bit R will check the
64-bit registry). It is looking for either of Software\JavaSoft\Java Runtime
Environment or Software\JavaSoft\Java Development Kit registry tree.

Cheers,
Simon

PS: Please uses stats-rosuda-devel mailing list for rJava questions.