[jdt-core-dev] where are the JDT refactorings' sources located?

[Gábor Kövesdán <gabor@xxxxxxxxxxxx>]

Dear JDT Core developers,

I'm getting prepared to apply for Google Summer of Code with an idea 
about extending current JDT refactoring features. I've looked at several 
wiki pages and docs and I've got the JDT Core sources and configured my 
workspace but I were unable to found where the refactoring features are 
implemented. Could you please give me a hint on this? And are there any 
other resources that may be useful for working on further refactorings?

Thanks in advance.

Regards,
Gábor