the best or speedest way to understand uncommented and complex project [closed]

Question

I have complex project without comments. The project is programed in Java but have more than one main class, use several .txt files like a template and use several .bat files. I don't know where to start and how to start discovering the project, because I need to make some changes in that project.

Answer 1

As with others I say this is a slow process.

However having done this in the past many times, this is my methodology:

1. Identify as many requirements that the code fulfils. This may give you the some reasons as to why certain things are the way they are when you look deeper. A common way of finding these is look for any tests that be available. The automated ones are best, but usually they're as missing as the comments.

2. Find the entry points to the code. These will give you places where you can poke the code to see how different inputs affect the flow. Common entry points are Code Loading 'Main' type functions, service interfaces, web page post backs etc..

3. Diagram the code. Look for tools that can build black/white box pictures of the code. For me this invaluable. I have on occasion printed out large listings and attacked then with markers and rulers. You're aim to create your own flow chart (mental or other wise) of the code flow.

4. Using the above (iteratively) build a set of outputs to the code that you think should occur, and add to these the outputs you may already know about such as logs, data files, database writes etc..

5. Finally if you have time, create some manual tests though preferably in automated test harnesses to verify the above. This where I start to involve the debugger to see detail in the code.

This methodology usually gives me confidence to make changes.

Note this is iterative process and can be done with portions of the code or overall as you see fit. I usually favour a top down approach to start with and then as I gain some insight I drill down till details become overwhelming and then I repeat. However this is just because my mind works in this way - you may be different. Good luck.