title: new File() with environment variables in Java
body: <p>How to get a File java object from its path string with environments vars?
  For example:</p>
  
  <pre><code>new File("%SYSTEM_ROOT%/file.txt")
  </code></pre>
  
  <p>or</p>
  
  <pre><code>new File("${SYSTEM_ROOT}/file.txt")
  </code></pre>