title: When to use environment variables vs. system properties?
body: <p>I wonder which of the following is a preferred approach?</p>
  
  <p>We can set things up as <code>APP_HOME=/path/to/file</code> (<code>export</code> in <code>.profile</code> or something along those lines) and access it as <code>System.getenv("APP_HOME")</code></p>
  
  <p>Or, alternatively using properties as <code>-DAPP_HOME=/path/to/file</code> and access it as <code>System.getProperty("APP_HOME")</code></p>
  
  <p>Now .. either one will make the value available for the application stand point, but is either approach preferred? Why? When?</p>