checking for null- how paranoid are you?
How paranoid is everyone in checking for null?
I have a program in which :
Any way null could be submitted as a member during object construction is checked for by a sentinel.
Contractually, consumers are obligated not to change the value of any object they get from the library (a requirement that makes sense in the given context which I won't go into).
Unmodifiable Collections are used throughout, but access to the individual objects is still possible, so contract ignoring developers could set an object to null- there's not way to stop them (and deep copies to objects accessible to consumers is not applicable, again you're spared the details)..
All entrance of nulls into the program from external libraries is checked- trouble can only come from consumers not following "the rules"
So given the above, how paranoid are you in checking for null? Any null found would necessarily result in an IllegalStateException and an end to the program.