Java return the Object/modify the object (coding guidelines)

Question

If a method populates/modifies an object, would it be preferable to return the object or to keep the return type as void and the method would modify the Object through its r

Answer 1

I would go with Command-Query separation generally.

That is to say, if the method mutates the argument, it should not also return the argument.

There are however (as noted in the wikipedia article above) situations where violating this general principle is appropriate.