When I am working on a web application I normally start Tomcat with mvn tomcat:run, change my source file (for example a JSP file), run mvn war:exploded to get the changed file in Tomcat and refresh my page in my web browser. And then I get to see my changed JSP.
Today I was working on a Maven based web project in NetBeans. I changed something in my JSP file, but I forgot to run mvn war:exploded before I refreshed the web page in my web browser. But to my surprise the change was already there on my screen. NetBeans had already copied my changes so Tomcat could picked it up. Wow! This really speeds up my development by factors. (my next step is to configure Tomcat in NetBeans...)