how you learn japanese in japan

Is there some way to learn Japanese NOT through in school or use internet byself .

Some cities/towns have international association or volunteer group that offer free/cheap Japanese language lesson. Lesson can be from textbook or just practice conversation skill.

Or you can just go to any international meetup or language exchange group.

Or just go to any izakaya or snack bar and start practicing/talking Japanese with the owner/worker or customer..

However most of these local classes at municipality administration arenft very good. You can improve your Japanese a bit, but even at a full time Japanese language school at least go people from not kanji countries it takes about 2 years of intensive studying to reach N1.
You can obviously study by yourself but for that you donft need to be in Japan.

Not sure if you are already in Japan. If not, youfll need a visa if you are staying longer than tourist gallowance g and for a student visa you need to be enrolled and attending your school.

From Books
From my Japanese girlfriend
Or From my Japanese Tomodachi
And all are free for Learning Japanese new words or sentence.

I learned quite a bit (not all standard dialect) by watching a lot of TV. I know somebody who learned by singing Japanese songs at karaoke.

You can learn by exposing yourself to Japanese media and also socializing with the people. A good way is to learn a bit of Japanese vocabulary and communication skill is through Kaimono (Shopping) or Ordering your food.