Yeah, I've had a couple of conversations with Japanese people who were surprised to hear that I need to have a job to maintain a visa, since they think foreigners can just come here and get money from the government for doing nothing. Japan accepts very few refugees, so realistically this isn't happening to the extent that people believe. Leaving aside whether immigration is a net positive or negative, the foreign population of Japan is almost entirely working, studying (on their own dime), owning a small business* or the spouse/child of someone doing one of those things.
*While there are some reports of rich people just creating something that meets the bare-minimum requirements of a "business" to get a visa, these people are independently wealthy and not collecting welfare payments.
*While there are some reports of rich people just creating something that meets the bare-minimum requirements of a "business" to get a visa, these people are independently wealthy and not collecting welfare payments.