What type of engineering are you doing and is it a bachelors degree? As an engineer myself, I've been told many times that my engineering degree carries a lot more weight than a Java Certification would, so I've never gone that route. I've also met people with Java Certifications who can't write any code, they can answer textbook exam questions about Java, but can't write anything usable (although I've also met brilliant self-taught developers who've done the Java Certification just to open up more job opportunities).
Unless you're studying something completely unrelated to programming, a Java Certification is probably not going to help you much if you're already doing an engineering degree. Get some Java books and teach yourself.