> Any hint for a tool which would it make easy to convert automatically a
> whole bunch of C structs to Java classes?
You need a full C parser with name and type resolution,
and the ability to generate Java code from same.
See http://www.semanticdesigns.com/Products/FrontEnds/CFrontEnd.html
for an appropriate parser, and the related discussion on the underlying
DMS Software Reengineering Toolkit.
Contact me offline for any further discussion.

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Ira Baxter, CTO
www.semanticdesigns.com