My suggestion is that you still need to include comments even though the code is self-explanatory. Your code may seems self-explanatory to you, but it may not to others. As every class has different properties, it is a good idea to include comments to explain what the properties are about and how you implement the class's requirements. Note that every students may use different variable names. It will helpful if you add the comments or explanation. The same applies to overriding methods, as every class will have different logic in the overridden implementations. You need to describe your intent and reasoning on how you implement the requirements.