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Ask HN: What tools do you use to understand big code-base?

9 points by c3c ↗ HN
You are given a big Java (or another language) project to contribute to. No documentation. How do you start? What tools do you use to understand the high-level structure of the code? Thanks HN!

11 comments

[ 2.3 ms ] story [ 38.5 ms ] thread
mtmail
Some of these old discussions might help. Ignore the answers pointing to documention. I once had to dive into a medium size Java web application without documentation and it took me half a day to even find out where data was stored (in a H2 database) nevermind trying to install it or finding out what changed between the repository and what I found on the live server. Ultimately told the client it will be cheaper for them to find another contractor. Best of luck.

Ask HN: How to understand the large codebase of an open-source project? https://news.ycombinator.com/item?id=16299125

Ask HN: Studying large code bases https://news.ycombinator.com/item?id=9060832

Ask HN: How to dive into large codebase? https://news.ycombinator.com/item?id=12142807

c3c
I can't believe there are no effective tools for that. Everything looks to be very low-level...
zunzun
doxygen turned the classes into hyperlinked web pages for a ginormous complex enterprise code base we worked on, it made understanding the code structure and class organization trivially easy - and we could email code structure links to each other for collaboration! For this purpose I rate doxygen as at least 11 or 12 out of a possible maximum of 10.
c3c
Does it create call diagrams by any chance?
zunzun
All method references are hyperlinked, so that you can click through and trace calls.
solomatov
I would use Intellij. The most important features are:

* Find usages (Alt+F7)

* Navigate by hierarchy (Ctrl+U/Ctrl+Alt+B)

Adamantcheese
I would have to agree. Find usages along with figuring out where/what variables are or used for will get you a long way. You can also go from the entry point and follow execution order, to the extent that you can.
in15minutes
Is it akin to "open definition" on methods? Does it summarize the call graph for you or just jumps you the calls?
_shadi
in addition to what was already suggested I use a notebook and a pen to keep track of interesting classes and write notes about them, like sort of an index, and I draw few flow charts.
tmm84
I used to be this way. I found that working in an editor using asciidoc/markdown is way easier for me. Copy/paste is faster than pen/paper. Also, I can write down notes and snippets of code to make life easier when I am trying to show someone what is going on in the source. Another advantage is I edit things to reflect the current state of the source and not get messed up by older notes/writings.