Changing the ServerAlias gives me an Index Of Page - .htaccess

Question

I'm a bit of a newbie when it comes to Server related stuffs, but basically I'm having the most frustrating problem right now...
My configuration file before being changed:
<VirtualHost *:80>
ServerAdmin xyz#gmail.com
DocumentRoot /var/www/xyz.net/public_html
ServerName www.xyz.net
ServerAlias xyz.net
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
<Directory "/var/www">
AllowOverride All
Order allow,deny
allow from all
</Directory>
Which is great, and it sort of worked. Although, going to www.xyz.net would load and you can see the content, however, going to xyz.net would show me an Index Of page. So I changed the config file, just switching the name and alias:
<VirtualHost *:80>
ServerAdmin xyz#gmail.com
DocumentRoot /var/www/xyz.net/public_html
ServerName xyz.net
ServerAlias www.xyz.net
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>
<Directory "/var/www">
AllowOverride All
Order allow,deny
allow from all
</Directory>
However, this doesn't seem to work, how come I'm still getting an Index Of page? Why is it that www.xyz.net has all the page content, yet xyz.net doesn't?! I'm really confused.
I've been trying to get www to redirect to non-www, at first I presumed it was an error with my .htaccess file, but after trying various methods of redirecting and even doing it in PHP, I presumed it was Apache screwing me over. So here's the code I use for the htaccess:
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
RewriteRule ^(.*)$ http://%1$1 [L,R=301]
edit:
Thanks for all the help, but everything loads fine on www.xyz.net, however on xyz.net an Index Of page is shown, and there are no indexed items in the list, so presumably it's just an empty web page.

Answer 1

Check if there is somewhere another virtualhost with ServerName: xyz.net. In such case, that other virtualhost can take precedence over yours virtualhost.
Under Linux based systems, there is a default config file which can contain this ServerName. By default, it's location is /etc/apache2/sites-available/default. The file can be also named 000-default.conf