Installation Error of Phantomjs (Linux) and rJava on RStudio Server

I would like to setup webdriver on RStudio AWS... install phantomjs, rJava, RSelenium, RSeleniumUtilities on RStudio Server AWS but failed. Any idea?

> Sys.info()
                                              sysname                                       release 
                                              "Linux"                           "3.13.0-55-generic" 
                                              version                                      nodename 
        "#94-Ubuntu SMP Thu Jun 18 00:27:10 UTC 2015"                             "ip-172-31-8-224" 
                                              machine                                         login 
                                             "x86_64"                                     "unknown" 
                                                 user                                effective_user 
                                            "rstudio"                                     "rstudio"  

> RSeleniumUtilities::checkSelenium()
  Error in list.files(java_path) : object 'java_path' not found
> Sys.getenv("LD_LIBRARY_PATH")
  [1] "/usr/lib/R/lib:/lib:/usr/lib/x86_64-linux-gnu:/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server"

Here is some reference for me but doesn't work. Phantomjs Linux,Installation error of rJava