How to make maven use system proxy settings

Did you take a look at http://maven.apache.org/guides/mini/guide-proxies.html?

In your settings.xml:

<settings>
  .
  .
  <proxies>
   <proxy>
      <active>true</active>
      <protocol>http</protocol>
      <host>proxy.somewhere.com</host>
      <port>8080</port>
      <username>proxyuser</username>
      <password>somepassword</password>
      <nonProxyHosts>www.google.com|*.somewhere.com</nonProxyHosts>
    </proxy>
  </proxies>
  .
  .
</settings>

NOTE: This doesn’t affect Java code! These proxy settings are Maven repository proxy settings.