You may or may not be able to secure a job before arriving home, you could however start the ball rolling, send your resume to some agencies, and line up some interviews before you come home.
Doing a certification will be a big plus. Depending on what type of career you are interested in, I would recommend doing the Sun SCJP or SCEA exams. With moderate Java experience you can do the SCJP with about 80 hours study/practice. If you have a broad (not necessarily deep) knowledge of J2EE, know UML, and design patterns, the SCEA is aslo achievable.