1. Run the program, look at stacktraces/profiler. Sometimes it's easier to analyze runtime and figure out what the program is doing and what are the main/common patterns.
E.g. Java - jstack, C++ - gdb, gprof
2. Use some static tools to get call/caller graph and be able to browse program quickly. Jump between definitions, see what's used, what's not.
E.g. C++ - docgen, Java - most modern IDE will do just fine
1. Run the program, look at stacktraces/profiler. Sometimes it's easier to analyze runtime and figure out what the program is doing and what are the main/common patterns.
E.g. Java - jstack, C++ - gdb, gprof
2. Use some static tools to get call/caller graph and be able to browse program quickly. Jump between definitions, see what's used, what's not.
E.g. C++ - docgen, Java - most modern IDE will do just fine