just like what Nyororin stated, intensive classes usually takes about 8 hours per day. Well that's the purpose of it. You need to be able to master Japanese language in just 1 year so it has to be that intensive. I think they need to memorize 10 kanji per day, so in about a month they should be able to memorize around 200 kanji, both reading and writing , or more on reading.. This is applicable to those taking the undergrad courses. But for those taking masteral or phd its a bit different depending upon the school and your field.
Like my bestfriend who was an took up masteral sponsored by jica was here for 2 years and I know for a fact that he can only speak basic Japanese. Enough to ask for direction
. They have interpreter at school and his adviser can also speak english. His thesis was all in english.
it all really depends upon your school, field or your interest in learning the language...