It depends on how certification is viewed in your place. In my own place, certification for software is not looked much at. CCNA, CCNP, MCSE, Sun, Comptia are the ones looked at. But when it comes to software, they just want samples of code you've written before. I remember i went ahead to do MCSD when i was in school and when i got out of school, no one even gave a look at it. If i'd had someone to advise me then, i'd have spent my time writing code for demo projects instead of reading to get certified.
My advise to you is to find some one who's Sun certified and get him to tell you if the certifications have helped him so far in getting
1. Position - Are they willing to give him a higher position or greater responsibility because he's Sun certified?
2. Money - Are they willing to pay him a higher salary because he's Sun certified?
If the answer is no, then just use your time getting some valuable experience. If it's yes, by all means get certified.