title: maven: what does ` -U,--update-snapshots` really do?
body: <p>In the command line help, I see that maven "checks" for updates:</p>
  
  <pre><code>-U,--update-snapshots                  Forces a check for updated
                                         releases and snapshots on remote
                                         repositories
  </code></pre>
  
  <p>However, most questions on Stack Overflow imply that this option forces Maven to update. Does this mean it forces a re-download of the dependencies?</p>
  
  <p>e.g. <a href="https://stackoverflow.com/a/9697970/1119779">https://stackoverflow.com/a/9697970/1119779</a></p>