I spent 20 years working in UK university departments, after taking a physics degree, mainly doing research & support in programming. I know the mind set of UK interviewers and they would, generally, think that taking a low level industry certification like this would show uncertainty in your own ability. You should have the level of knowledge in this certification already (perhaps lacking a few odds and ends that are not important anyway.)
Anyone can work at Microsoft.
Someone looking to do physics research should look on certification as a joke and read Bessier & write some advanced numerical analysis programs. Then you'll have something to impress them, maybe...
So I stand by 'it's worse than nothing' because taking the qualification will make you look like a pushy amateur. Also by doing nothing you will give your brain a rest (always useful -- see Einstein on the subject). You are going into your final year, where you will (should be) be working non-stop on physics. Hacking through a Java certification will only leave you feeling jaded.
My best advice would be -- holiday! Lie on the beach for two weeks, then do interesting stuff (visit Rome, go an archaeological dig, play tennis, whatever floats your boat). Give your physics brain a rest and show that you're a rounded person... your account of the Vatican (say) would be much more appreciated by an interviewer than a Java certification score...