Unable to load rJava on R

Question

I wish to load rJava in R x64 3.1.2. OS- Windows 8.1 64 bit

Though installation seems to work fine:

  > install.packages(\"rJava\")
    Installing         


        

Answer 1

I get this error every time Java sneaks an update onto my PC. When I go:

Sys.getenv("Path")

I find something in the output which looks like

C:\\Program Files \\Java\\jre1.8.0_112\\bin\\server\\

where the last few digits of the jre subfolder are outdated.

To fix this everywhere, you might want to edit the Windows environment variable. Do this by going WINDOWS + X key, selecting Command Prompt (Admin) from the menu, and typing

rundll32.exe sysdm.cpl,EditEnvironmentVariables

in the command box. This will call up this dialog box with edit rights for the PATH variable (and other system variables):

The Windows interface for editing long environment variables is a bit unwieldy, so after I click Edit... I like to copy-paste the resulting mess of paths to Notepad.exe, do the work there, and copy-paste back.

Answer 2

I've met a similar problem and spent an entire day to get it fixed. Although my computer, windows7, and Rstudio are 64 bit, but my Java is 32 bit(!) Once I realized that, I download a 64 bit Java. I have to manually download, the automatic download will lead to the 32 bit version because my chrome browser is 32 bit. 64 bit Java will be automatically installed in

C:\Program Files\Java, however, 32 bit Java will be automatically installed in C:\Program Files (x86) \Java.

This is an important indicator telling me my Java is 64 bit or 32 bit.

After installing the 64 bit Java, everything works perfect!

Answer 3

Try downloading the RStudio daily build: http://dailies.rstudio.com

It worked for me on the second try after I tried everything else (updated R, Rstudio, Java, reinstalled rJava a million times, and followed all the stackoverflow advice).

The tip came from the RStudio support forums:

RStudio is indeed failing to read some of the start-up information normally provided by R here...

We have a potential fix for this in the latest daily builds of RStudio -- if you're willing, you can try downloading and testing from http://dailies.rstudio.com

Answer 4

I got a similar error:

> library(rJava)
Error : .onLoad failed in loadNamespace() for 'rJava', details:
  call: inDL(x, as.logical(local), as.logical(now), ...)
  error: unable to load shared object 'C:/program files/R/R-3.1.2/library/rJava/libs/x64/rJava.dll':
  LoadLibrary failure:  The specified module could not be found.

My JAVA_HOME was pointing to JDK, rather than JRE.

> Sys.getenv("JAVA_HOME")
[1] "c:\\java\\jdk1.7.0_55"
> Sys.setenv(JAVA_HOME="c:\\java\\jdk1.7.0_55\\jre")

I could now load rJava and xlsx in R.

Answer 5

Had the same issue:

I was running 64-bit R you can check which version by closing and re-openning RStudio. It should be at the top.

I had 32-bit java installed i.e. Java folder was within C:\Program Files (x86).

I simply went on to Java.com and downloaded the 64-bit Java and added it's location at the end of the PATH in System variables and I can load rJava now. (The installation asked me to get rid of the old version which I did)

Answer 6

Use:

Sys.setenv(JAVA_HOME='...path to JRE...')

e.g.

Sys.setenv(JAVA_HOME='C:\\Program Files\\Java\\jdk1.7.0_51\\jre')

Your environment variable is wrong.