So, first of all my code editor will only tell me that which line is creating exception. If not, I'll start, I'll follow a top-down approach and I'll check which are the connections which might create a problem. What are the things which I am using outside the code like server or etc. which might create an exception. I'll list it down in an object and one by one I'll check everything. I can do the testing also, like unit testing, I'll check every unit of my code or then I'll do integration testing one by one so I can really find out what is a bug inside my code. I can perform testing.
