Understanding large Java Code Base

Question

Are there resources on going about trying to understand a large java code base. Like for example, a graph persistence implementation. If there is minimal / missing documentation, what kinds of approaches do you take ? Are there any books that deal with this ? I know one called Brownfield App Development in .NET.

Perhaps something similar ?

Answer 1

There are number of ways to tackle such a problem and most of the times it will be your personal preference and style of coding and solving problems... for ex:

1. Start with any documentation/TDD if available.
2. Use some design/UML tool like EA Architect to generate the UML/Class diagram to understand the class structure.
3. If the project has some test cases, start by executing and understanding the code behind it.
4. Try running the application and you can set some debug points and try understanding the flow.

End of the day it all depends on the project, how well the code is documented and your personal style of solving problems.

Answer 2

My suggestions would be:

1. Get the code building. If there is no build script, write one.
2. Get the code running.
3. If there are no tests, start picking off bits of the system to write tests for. You're not really testing, you're learning about the system's behaviour.
4. Use a modern IDE (Eclipse, Netbeans, etc.) to start tracing the declarations and references to methods and classes.

Good luck!

Ian.