I am trying to upload a PDF file to a Chatter feed in my Java web application.
It works fine with v25.0, but when i try to use v27.0 it does not work anymore and response status code is 500 - Internal Server error?

I'm using the example code from Chatter REST API page number 138:
http://www.salesforce.com/us/developer/docs/chatterapi/salesforce_chatter_rest_api.pdf

Any ideas to work this around?