title: When to check for null's?
body: <p>Should I check for passing of null values for values that need to be valid in constructors? In other words, should I have the class throw when it gets an invalid value, or should I let it be until it tries to do something with it, letting the runtime raise the exception? </p>
  
  <p>I suppose if passing a null value is an error, I should treat it as such in the constructor? </p>