"The Java language automatically initializes fields of objects, in contrast to local variables of methods that the programmers are responsible for initializing. Given what you know of intra- and inter-procedural data flow analysis, explain why the language designers may have made these design choices."
Its obvious to me that its to prevent a bug. However, what exactly is that bug? Would it be to condense the possible control flow of some given method?
Could someone go into greater detail on this? I'd really appreciate the help.
It's really easy to do intra-procedural data flow, so it's really easy to check whether a field has been initialized and give warnings if it hasn't (one can write a simplistic decidable algorithm, e.g. make sure all branches of an if initialize a variable, and if one branch doesn't, fail, even if the branch is unreachable).
It's really hard to do inter-procedural data flow, so it's really hard to check whether a field of an object has ever been initialized anywhere in the code (you quickly get into undecidable territory for any reasonable approximation).
Thus Java does the former and gives compile-time errors when it detects uninitialized local variables, but doesn't do the latter and initializes an object's fields to their defaults.