AMHERST, Mass. - Students walking into the course, "Homelessness and Shelter," often enter the classroom with some anxiety, says the Rev. Christopher Carlisle, Episcopal chaplain at the University of Massachusetts. "We''ve all been taught that the homeless are someone to avoid, to avert one''s eyes from, and at best to throw a quarter at." Yet a few months later, the students generally leave with a feeling that "a great deal of homelessness has to do with bad luck, and it has a searing injustice," said Carlisle.