To dream of seeing students in a classroom suggests that you may be learning an important life lesson.
If you are a student, this dream can also reflect feelings or anxieties about real life classes.
If you dream about your current classmates, they may represent aspects of your own personality. Look to the people you dreamed about for signals of personality traits they have that you desire in yourself, or that you wish to get rid of.
If you dream of former classmates (from years gone by), this suggests that you need to draw on your old associations with your former classmates to gain insight in some current relationship. You learned a lesson from your relationships with the person or people you were dreaming about, and that lesson can help you in some aspect of your life now.
So look to the people you dreamed of, and the experiences you had with them, for clues to how to act in a current situation or relationship.