A spawn off of an existing eclipse product is required for customization for a client. (hence parallel product development)

The intention was to use Eclipse Fragment, but "Fragments are additive, they cannot override content found in the host."

how can we maintain one set of codes in the svn, yet allow customization by overriding some classes?

the current solution is to have a global flag to indicated which product it is and "if" "else" littered everywhere in the codes ...