Retrofitting void methods to return its argument to facilitate fluency: breaking change?

Question

\"API design is like sex: make one mistake and support it for the rest of your life\" _{(Josh Bloch on twitter)}

There

Answer 1

If you can't retrofit, you still can wrap your class into a new one which uses the same methods but with correct returns (MyClassFluent). Or you can add new methods but with different names, instead of Arrays.sort() we could have Arrays.getSorted().

I think that the solution isn't to force things, just deal with them.

EDIT: I know I didn't answer to the "retrofitting of void methods" question, but your answer is already really clear.