I'm not sure what Oracle's presence in Japan is, but if you can get a company to sponsor your move to Japan and pay you a non-Japanese salary, you'll be so far ahead of the game it will not even be comparable to the experience of Japanese citizen employees. In general pay ranges from 40-60% of equivalent jobs in the USA, but can require commonly a 50 hour workweek that can slide toward 60 hours per week without much reason for it.

Another option is living here but working remotely; I've seen it done, particularly with programmers. And because of the wage discrepancy, even if you take a wage hit, you'll still be making more than working code for a Japanese company.

OTOH, if your work is at all relevant to the financial sector you will be more able to command a livable wage - or even an exorbitant wage.

Here is a thread relating to some of this, where an IT professional is looking to move:
tokyopia.com/tk/forum/index.php
There are many other threads in that forum about living in Japan and working as well.