Hi Tim!

I do not know the code you are talking about, so a specifical discussion about your special case would be frivolous.
I can just tell you about my experience concerning exception handling in general and NullPointerExceptions in particular.

First I think we must distinguish between inter-component and intra-component communication. The former is the communication between
components which should be done using the component's public APIs. The latter is the communication between component-internal
objects which uses the public- and non-public-API of the component.

The public API of a component should do parameter checking - and a wrong/illegal parameter should produce an
IllegalArgumentException - especially if an input parameter is null but it mustn't.

The non-public API is component-internal and often used by the component-developer itself only. So often there is no need for
parameter checking. Think of a situation where the public API of a component calls an internal method which again calls internal
methods and so on, and each called method hands on its input parameter. If each method did input validation, the same variable would
be checked again and again - e.g. against null - although the public API already ensured that the parameter is not null! Thats an
unnecessary effort!
As a result, illegal parameters inside non-public API methods might produce a NullPointerException - or any other exception
according to the algorithm that uses the parameters.

But in both cases - public and non-public-API an exception is what it says: An non-standard termination of the method call! A thrown
non-checked exception (i.e. RuntimeExceptions and subclasses - like NullPointerException) almost always meanst that there is a bug
in the code - otherwise you would have expected the exception and use a checked exception instead that MUST be catched or rethrown
by the caller. Illegal user input is NO bug (ok, often it is a brain-bug of the user, but not a bug of the software) - so there
should never be thrown an non-checked exception in that case (as always: The exception proves the rule)!

Please tell me your opinion about that!

Best regards,
 Tex

(BTW: Should/Must software always be "bullet proof"? I'm currently building a house - my windows aren't bullet proof! Of course - I
wish it was, but that's a matter of optics (the thick glass) and costs!)