[Building Sakai] Velocity in Sakai

[le tan vu]

Hello all!
First of all, thank you for your helps since the first time I make question
on sakai-dev mailing list.

Today I want to ask about Velocity in Sakai.
I'm working on tool Assignment1 in order to modify it. So I must understand
Velocity although it was old.

I followed the instruction at
http://confluence.sakaiproject.org/display/BOOT/The+Simplest+Possible+Sakai+Tool
and I was successful with simple servlet example. After that, I modify that
example to use Velocity as presentation but I failed.
I used *VelocityServlet* as superclass and override the *handleRequest
method*.
I configured *web.xml* and *velocity.properties *as the assignment tool did.
But I could not load the template.
I tried to put relative path and absolute path into *velocity.properties
file* but nothing happened. How can I load template in Sakai? (in other
small example, absolute path in *velocity.properties* worked!)

Moreover, How can I find a clear tutorial or example about using Velocity in
Sakai. Although it was used as the most display technology in Sakai but I
seem not to be able to find a good document to use it in Sakai framework (
among documents in confluence site).

I attach my source code below. Very light. Please look at it.
I'm working on Sakai 2.6.0.

Any help would be appreciated.
Thanks in advanced.
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