.onLoad failed in loadNamespace() for 'rJava' when installing a package

Question

I have a package "javaOnLoadFailed" (just a minimal package for testing my issue, hence the weird name) which imports rJava. I get 'rJava' errors when I try to either check() or install() the package, even though require(rJava) itself works fine.

install() gives the following errors:

> install()
Installing javaOnloadFailed
"C:/Program Files/R/R-3.2.0/bin/x64/R" --no-site-file --no-environ --no-save  \
--no-restore CMD INSTALL  \
"C:/Projects/stackoverflow/javaOnloadFailed/javaOnLoadFailed"  \
--library="C:/Users/adb2018/Documents/R/win-library/3.2" --with-keep.source  \
--install-tests 

* installing *source* package 'javaOnloadFailed' ...
** R
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded
*** arch - i386
Error : .onLoad failed in loadNamespace() for 'rJava', details:
  call: inDL(x, as.logical(local), as.logical(now), ...)
  error: unable to load shared object 'C:/Users/adb2018/Documents/R/win-library/3.2/rJava/libs/i386/rJava.dll':
  LoadLibrary failure:  %1 is not a valid Win32 application.

Error: loading failed
Execution halted
*** arch - x64
ERROR: loading failed for 'i386'
* removing 'C:/Users/adb2018/Documents/R/win-library/3.2/javaOnloadFailed'
Error: Command failed (1)

I am using R 3.2.0 from within Architect, with sessionInfo():

R version 3.2.0 (2015-04-16)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 7 x64 (build 7601) Service Pack 1

locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] devtools_1.7.0.9000 rj_2.0.3-2         

loaded via a namespace (and not attached):
[1] tools_3.2.0   rj.gd_2.0.0-1

Answer 1

The Java environment variable is empty

> Sys.getenv('JAVA')
[1] ""

Based on a suggestion, I tried setting the JAVA environment variable to point to the 64 Bit version of Java (because I am running R 64 bit, as you could see from the sessionInfo, but that doesn't work:

> Sys.setenv(JAVA_HOME='C:\\Program Files\\Java\\jre1.8.0_45')
> install()
Installing javaOnloadFailed
"C:/Program Files/R/R-3.2.0/bin/x64/R" --no-site-file --no-environ --no-save  \
  --no-restore CMD INSTALL  \
  "C:/Projects/stackoverflow/javaOnloadFailed/javaOnLoadFailed"  \
  --library="C:/Users/adb2018/Documents/R/win-library/3.2" --with-keep.source  \
  --install-tests 

* installing *source* package 'javaOnloadFailed' ...
** R
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded
*** arch - i386
Error : .onLoad failed in loadNamespace() for 'rJava', details:
  call: inDL(x, as.logical(local), as.logical(now), ...)
  error: unable to load shared object 'C:/Users/adb2018/Documents/R/win-library/3.2/rJava/libs/i386/rJava.dll':
  LoadLibrary failure:  %1 is not a valid Win32 application.

Error: loading failed
Execution halted
*** arch - x64
ERROR: loading failed for 'i386'
* removing 'C:/Users/adb2018/Documents/R/win-library/3.2/javaOnloadFailed'
Error: Command failed (1)

I then tried to set the JAVA environment variable such that it points to the 32 bit version of Java on my system, and then it works!

> Sys.setenv(JAVA_HOME='C:\\Program Files (x86)\\Java\\jre1.8.0_45\\')
> install()
Installing javaOnloadFailed
"C:/Program Files/R/R-3.2.0/bin/x64/R" --no-site-file --no-environ --no-save  \
  --no-restore CMD INSTALL  \
  "C:/Projects/stackoverflow/javaOnloadFailed/javaOnLoadFailed"  \
  --library="C:/Users/adb2018/Documents/R/win-library/3.2" --with-keep.source  \
  --install-tests 

* installing *source* package 'javaOnloadFailed' ...
** R
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded
*** arch - i386
*** arch - x64
* DONE (javaOnloadFailed)

[INFO] Updating the R environment index started...

[INFO] The R environment index was updated successfully.

I don't quite understand why I need to point to Java 32 bit to make R 64 bit work, but that's what seems to be the case.

By the way, don't stumble over my package name "javaOnLoadFailed". I just created a minimal package with that name to test the problem.