Sharpen is an Eclipse plugin which can covert Java code to C#. This free plugin has been implemented by db4o.
See the following pages for more information:
Product description: http://developer.db4o.com/Projects/html/projectspaces/db4o_product_design/sharpen.html
User guide: http://developer.db4o.com/Documentation/Reference/db4o-7.12/java/reference/html/reference/sharpen.html
Source code: https://source.db4o.com/db4o/trunk/sandbox/blogs/SharpenExamples/ContactList