title: R: Cannot install rJava; what is r-api-3.4?
body: <p>I am on an Ubuntu 18.04 machine with R version 3.5.1, installed following <a href="https://cran.r-project.org/bin/linux/ubuntu/" rel="noreferrer">this link</a>. I am trying to install the CRAN package <strong>rJava</strong>, which I do the following way (as seen <a href="https://askubuntu.com/questions/858961/install-rjava-on-ubuntu-failed">here</a>):</p>
  
  <pre><code>sudo apt-get install r-cran-rjava
  </code></pre>
  
  <p>However, I get this:</p>
  
  <pre><code>The following packages have unmet dependencies:
   r-cran-rjava : Depends: r-api-3.4
  E: Unable to correct problems, you have held broken packages.
  </code></pre>
  
  <p>But when I try:</p>
  
  <pre><code>sudo apt-get install r-api-3.4
  </code></pre>
  
  <p>I get:</p>
  
  <pre><code>E: Package 'r-api-3.4' has no installation candidate
  </code></pre>
  
  <p>How to overcome this problem with <code>r-api-3.4</code>? Basically, I need to install <code>rJava</code> to be able to install and use <code>XLConnect</code>... In Ubuntu 16.04, I had no problems whatsoever...</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>Apparently, <code>r-api-3.4</code> should be provided by <code>r-base-core</code>. I do have <code>r-base-core</code> installed in its newest version, why do I still see errors then?</p>