Some people may assume that criminology and criminal justice are the same. The truth is that they are not. When you say criminology, this means that you are studying crime and all of the things that are related to it. When you say criminal justice, this means that you are trying to describe how people in society usually respond to a type of crime.
Take note that the criminal justice system can be very complicated. There are instances when there are various components that will be used to enforce various laws or to actually check out the different crimes that are available. The main purpose of criminology is to not only serve justice but also to make sure that those who are convicted will undergo proper rehabilitation.