I am working on a large J2EE application. I am not very familiar with front end development, and I am trying to trace through the entire application(not in one shot). I am looking at a test case right now and know how to create the problem (functionally) now I am wondering how to stop the code at this specific spot in order to trace through the full stack environment... Are there any tips you can give me?
The typical solution with unfamiliar, large code bases is to "divide" the mass of code in two, repeatedly (binary subdivision). I put the word in quotes as it is not always easy to figure out how to divide the code.
First you must be able to identify the problem in the debugger or via trace output -- not via a UI. Then identify at least some of the code executed at the highest level. Then put a breakpoint into approximately what you consider "half way" through the mass of code executed. At that breakpoint, you check the condition to see if the bug occurred. If not, you try to find a point in the code halfway before that, put a breakpoint, and so on.
If the condition representing the bug has occurred, you try to find a point half way through the remainder of the code, and so forth.
If you have extensive logging and have one point in the code where much of the logging is emitted, you can put a breakpoint at that location, ideally a conditional breakpoint -- it won't break unless the error condition occurs. This is a much faster technique as you narrow in faster.