Enthuware

I have a question with option 4:
if ( (str == null) || (i == str.length() ) )

Imagine the following scenario:
Now let's say that string is some non-threadsafe variable and after executing the first part of the if-statement (str == null, which is false) another thread modifies the variable str and sets it to null, the original thread continues evaluating the if-statement and it fails with a NPE because the other thread has set the str to null?

You are right. It is possible. The problem statement has now been updated to make it clear that str is a local variable to eliminate the situation you described.

thank you for your feedback!
Paul.