The code & the comment
Today I found the simple code with the even more simple comment:
[...]
if (entry== null)
return; // should not happen
[...]
What if the "if" just happened?
The Finagle's law is:
Anything that can go wrong, will—at the worst possible moment.
Especially in IT it is true. Unfortunately I saw variation of above code many times, which is completely sad.
Fail fast
In my private opinion the best way is to fail fast. I know that user/system/boss will be sad/broke/angry, but if abnormal situation happen even once you will be know about it.
So the easiest way is to
if (variable == null)
throw new Exception("Oh my god the universe just doomed: entry is null");
but I cannot
If you really cannot throw an Exception, log this error. Log it in standard way with all needed information like: stack trace, context, etc. It should be easy to access as all your logs.
The perfect solution
The perfect solution is simple: combine logging and exception. This should allow to track fast what exactly happened, which should not happened