In order to get it to work right, I have to “drop and drag” the files that I want in my classpath/dependencies into my the WEB-INF/lib folder. It works this way.
For some reason, when I try to do it the right way
Build path → Configure build path → External jars
it just doesn’t take them.
The trick is that I have to put the files int my Web App Libraries folder and the only way to do that (that I can see) is to “click and drop” into my WEB-INF/lib folder. In this way, it automatically shows up in my Web App Libraries.