The best way to familiarize yourself with an inherited codebase

Question

Stacker Nobody asked about the most shocking thing new programmers find as they enter the field.

Very high on the list, is the impact of inheriting a codebase with which

Answer 1

The first thing I do before going down into code is to use the application (as several different users, if necessary) to understand all the functionalities and see how they connect (how information flows inside the application).

After that I examine the framework in which the application was built, so that I can make a direct relationship between all the interfaces I have just seen with some View or UI code.

Then I look at the database and any database commands handling layer (if applicable), to understand how that information (which users manipulate) is stored and how it goes to and comes from the application

Finally, after learning where data comes from and how it is displayed I look at the business logic layer to see how data gets transformed.

I believe every application architecture can de divided like this and knowning the overall function (a who is who in your application) might be beneficial before really debugging it or adding new stuff - that is, if you have enough time to do so.

And yes, it also helps a lot to talk with someone who developed the current version of the software. However, if he/she is going to leave the company soon, keep a note on his/her wish list (what they wanted to do for the project but were unable to because of budget contraints).