[Building Sakai] upload file with tomahawk in Sakai

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Hi,

I'm trying to create a little tool using JSF . I want to implement an "upload 
file" so I used tomahawk,  but I encountered java.lang.NullPointerException. I 
did specify my form enctype="multipart/form-data" and config the 
ExtensionsFilter in web.xml. I also tried the same configuration on an JSF 
project outside Sakai and it run completely fine. I include my web.xml, 
faces-config, the backing bean and the jsp page. Can somebody help me fix this 
or tell me other way to implement a file uploading in Sakai with JSF.

I am actually learning wicket too. And I know it much better to maintaince but 
for this project I don't have much time left and I am more familiar with JSF. I 
will switch to wicket after this, I saw project of JSF like Samigo and 
understand the elegent of Wicket. But for now please help me with this.

Thanks a lot.

-- PVHoa
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