Can i study in japan

without being admitted by the college.i was thinking if i get a student visa, go to japan, find an apartment before living to japan and then apply at the school.

I believe you need to apply for admission with a school/college first, get admitted, and pay in the tuition before any student visa procedure can be started.

Or you *could* come on another type of status (Temporary Visitor Status, or Working Holiday Visa status if you qualify in terms of nationality) initially, then while in Japan apply with a school/college and change your status to student. But you will need to be prepared with all the documents when you come to Japan, otherwise you will have to go back/ask family to send you documents, etc.