Rstudio does not see rJava under Ubuntu 12.04

library(rJava) in Rstudio gives the error :

Error : .onLoad failed in loadNamespace() for 'rJava', details:
  call: dyn.load(file, DLLpath = DLLpath, ...)
  error: unable to load shared object '/home/anh/Rlibs/rJava/libs/rJava.so':
  libjvm.so: cannot open shared object file: No such file or directory 

Solution : add
export LD_LIBRARY_PATH=/usr/lib/jvm/java-8-oracle/lib/amd64:/usr/lib/jvm/java-8-oracle/jre/lib/amd64/server

into /etc/bash.bashrc , then run

. /etc/bash.bashrc

then run

sudo R CMD javareconf

then restart Rstudio