Hey Mac OSX users with Java 1.8 installed. Did R just request a Java 1.6 installation and then promptly crash your session?  If so, read on…

The Problem

A few days ago I was attempting to use the mallet package for topic models and I found that typing

> library(mallet)

caused two things to happen:

1. The operating system launches a dialog asking whether I would like to download Java 1.6
2. The R session crashes (regardless of what I did about the dialog)

This seems to be a general problem for packages that depends on the rJava package.

I’m running the latest Mac OSX (Yosemite 10.10.1) and have installed the latest Java

$ java -version
java version "1.8.0"
Java(TM) SE Runtime Environment (build 1.8.0-b132)
Java HotSpot(TM) 64-Bit Server VM (build 25.0-b70, mixed mode)

and the latest R

$ R --version
R version 3.1.2 (2014-10-31) -- "Pumpkin Helmet"
Copyright (C) 2014 The R Foundation for Statistical Computing
Platform: x86_64-apple-darwin13.4.0 (64-bit)

But for some reason with R, it’s Java 1.6 (which is no longer even being updated) or bust.

The fix (maybe)

The trail of bug reports starts here, but before you delve into those and bother Simon Urbanek as much as I did, try the following:

1. Download and install Apple’s Java version 1.6 like you were asked to.
2. Reconfigure your R installation by typing

   sudo R CMD javareconf -n

   in a Terminal window

3. Trigger a recompile by reinstalling rJava by typing

   install.packages('rJava', type='source')

Now if you relauch R and load your package it should use your shiny new Java 1.8 and not crash any R sessions.