Things to do after a fresh Ubuntu install

Some libs that you need to install for R to work properly on a Ubuntu machine:

sudo apt-get install libcurl4-openssl-dev libxml2 

To keep R up-to-date, edit /etc/apt/sources.list and add the line:

deb http://cran-mirror.cs.uu.nl/bin/linux/ubuntu vivid/

Change vivid to your Ubuntu version, of course. You can also use a different mirror site.

Set up Java:

sudo add-apt-repository ppa:webupd8team/java -y
sudo apt-get update
sudo apt-get install oracle-java8-installer
sudo apt-get install oracle-java8-set-default

Set Java-related environment variables.

export JAVA_HOME=/usr/lib/jvm/java-7-oracle/
export LD_LIBRARY_PATH=$JAVA_HOME/jre/lib/amd64:$JAVA_HOME/jre/lib/amd64/server

Configure Java with R:

sudo R CMD javareconf