Why does Tiles 3 require so many dependencies?

[Andrey Botalov]

I write a very simple Tiles app that doesn't use any features besides 
those in http://tiles.apache.org/framework/tutorial/basic/index.html. 
You can see stuff relevant to Tiles at https://gist.github.com/3324728

When I try to run it, I become overloaded with NoClassDefFoundErrors. 
Many of those are in \lib\optional folder of tiles-3.0.1-bin.zip so I 
don't think that I need them (e.g. spring-core, spring-web, ognl,mvel). 
Do I need them in my simple Struts app?