D. Ogranos is right. Assume s is null.
will never throw because you know that Left Hand Side string at the compile time itself that it can not be null. And putting a '.' operator on a non-null object will always let your program go smoothly without exceptions.
Else you would be required to code like this:
which unnecessarily brings in another && condition. Ofcourse, there could be tradeoffs if one could not easily understand why you have used "abc".equals(..) instead of the other approach.