Simplest option - for your webapp, create an index.html file which does
not do anything. This will be picked up and rendered, instead of the
directory listing.

Second option is via global web.xml. It is in $CATALINA_HOME/conf.
Under default servlet section (<servlet-name>default</servlet-name>)
you will see an init-param for directory listing, which is true by
default. Turn it to false and you should be good to go after bouncing
tomcat.

<init-param>
       <param-name>listings</param-name>
       <param-value>false</param-value>
</init-param>

-cheers,
Manish

Issue was this
Under <servlet-name> we had 2 <init-param> for <param-name>listings
the first one False, as should be, the second one was True.  So the
second one made it so you could list the directory.

Remember to just change the line, and add a new one when editing the
web.xml