Although i didnt get what you are asking . I am still trying to answer.
Every college has their own credit system. Most of the time in colleges number of credits for a particular course is equal to the number of hours you gonna have a class for that course .For an instance if you have 3 credit Java course then in total you gonna have 3 hours java class in a week (depends on the instructor he/she can divide the class in two one and half hour classes). If in the end you pass that course , you will get credits and if not you wont get credit and you have to take that course again. In most of the colleges fee for the course also depends upon the number of credits that course has.