Where to check if an object is null or not?

Question

Where do you check if an object that you are passing to a method is null or not?

Should an object need to be tested before calling a method? or within the method tha

Answer 1

I prefer null checks inside methods for two reasons.

1. I think functions should be 'complete', ie handle null values/'edge cases' and not rely on callers. This is for two reasons,

   • someone calling the method later might forget to add null checks
   • it's easier to test the method with edge cases in unit tests.

2. having null checks inside the method reduces overall number of null checks inside the code, which usually means more readable code