ServletContext getContextPath()

I checked the javadocs of the Tomcat library I have included under my Netbeans project, and when I deploy the code works fine, but when I do a clean-build of my web project I get a "cannot find symbol" on the getContextPath() method of the ServletContext interface

It's driving me completely insane because in order to run my tests and so on I have to first deploy, then test, if I clean and build, or clean and run tests I get this error...

Anyone have any clue what could be causing this issue? Is there a library I have to update or something?