You should have the chance to travel there and observe for yourself!
I've been to Hawaii several times. Yes, there are some illegals there, but they certainly aren't from Japan, and few, if any, arrived in Hawaii by ship.
Illegals in Hawaii are mainly from Mexico or other Latin American countries, and they work construction. They illegally enter via the Southern border and then catch a plane to Hawaii, though they most likely spend a few years on the mainland working jobs before landing one out in Hawaii.