Question

For example, GWT 2.4.0 still complains “Field ‘private final…’ will not be serialized because it is final”.

The easiest way is to add a setter (or any dummy-method, making the assignment of local variable, which we want to prevent becoming final (if, for instance, setter already have and it does not assign)).

Answer 1

You can find the settings under Window > Preferences > Java > Editor > Save Actions > Additional Actions > Configure... > Code Style

And regarding your comment:

I want to disable adding the modifier to a single line, not the entire
project.

Eclipse doesn’t really have a clean way to do this. What you could do is just open the file with the Eclipse Text Editor instead of the Java Editor and delete the final keyword manually, but I’m afraid there’s not much you can do beyond that.

Or create an unused method that re-assigns the field, but that’s kind of hacky as well.