How to find JNDI name when creating entity classes from a database?

I'm using NetBeans 8.0.2 to create a web app that can create, read, update, and delete from a database. I was following this tutorial (http://ift.tt/1g9HgFa), but ran into an issue when I was creating the entity files. However, the window in which I am supposed to enter the data source to draw from requires a JNDI Name and Database Connection.

The connection is easy enough, since it's the name of the database I already have loaded through NetBeans. However, I have no idea what the JNDI name should be, and following the model name provided by the tutorial doesn't work. When I try that, or any other name, I get an error in the server log, which reads:

Severe:   Exception while preparing the app : Invalid resource : [" whatever name I entered"]

I found almost no information online regarding this problem or how to look up a JNDI name.