public Update downloadPlugin(String url) {
        UpdateManager updateManager = XMPPServer.getInstance().getUpdateManager();
        updateManager.downloadPlugin(url);

        Update returnUpdate = null;
        for (Update update : updateManager.getPluginUpdates()) {
            if (update.getURL().equals(url)) {
                returnUpdate = update;
                break;
            }
        }

        return returnUpdate;
    }
Starts the download process of a given plugin with it's URL.

@param url the url of the plugin to download.
@return the Update.
xmppserver/src/main/java/org/jivesoftware/openfire/update/PluginDownloadManager.java