Here is some quick advice on how to get up and running with R + rJava on Windows 7 64bit. There are several possibilities, but most have fatal flaws. Here is what worked for me:
Add jvm.dll to your PATH
rJava, the RJava bridge, will need jvm.dll, but R will have trouble finding that DLL. It resides in a folder likeC:\ProgramFiles\Java\jdk1.6.0_25\jre\bin\server
orC:\ProgramFiles\Java\jre6\jre\bin\client
Wherever yours is, add that directory to your windows PATH variable. (Windows -> "Path" -> "Edit environment variables to for your account" -> PATH -> edit the value.)
You may already have Java on your PATH. If so you should find the client/server directory in the same Java "home" dir as the one already on your PATH.
To be safe, make sure your architectures match.If you have Java in Program Files, it is 64-bit, so you ought to run R64. If you have Java in Program Files (x86), that's 32-bit, so you use plain 32-bit R.
Re-launch R from the Windows Menu
If R is running, quit.
From the Start Menu , Start R / RGUI, RStudio. This is very important, to make R pick up your PATH changes.
Install rJava 0.9.2.
Earlier versions do not work! Mirrors are not up-to-date, so go to the source at www.rforge.net: http://www.rforge.net/rJava/files/. Note the advice there“Pleaseuse`install.packages('rJava',,'http://www.rforge.net/')`to install.”
That is almost correct. This actually works:
install.packages('rJava', .libPaths()[1], 'http://www.rforge.net/')
Watch the punctuation! The mysterious “.libPaths()[1],” just tells R to install the package in the primary library directory. For some reason, leaving the value blank doesn’t work, even though it should default.