NetBeans doesn't create a war file when you run deploy. It just registers the "build" directory as a webapplication with Tomcat.
Check out $CATALINA_HOME/conf/Catalina/localhost
there should be a file yourapp.xml
Where yourapp
is the "context path" you specified for your project ("Project Properties -> Run")
The XML file contains only single entry, something like this:
<?xml version="1.0" encoding="UTF-8"?>
<Context antiJARLocking="true" docBase="/path/to/your/project/build/web" path="/yourapp"/>
Due to this configuration file, Tomcat is able to run your web application