Re: HashMap get/put
Wojtek wrote:
Lew wrote :
FWIW, if 'Map#get()' had been redefined generically, it would have
broken existing code without providing an improvement. Code that
would have not gotten a value still does not get a value without
introducing a new error. Maybe they erred in this, but they were
trying to maintain backward compatibility.
All sorts of code broke when generics were introduced. Every use of each
class which had generics needed to be changed. Also changing get() would
just have been done at that time.
It's a shame that the compiler didn't find your refactoring mistake
for you, but it was your mistake, not Java's.
Of course it was my mistake. That is what I am saying. And that is why
we have compilers which report mistakes, so that they may be caught
BEFORE they show up during runtime and "weird things" happen.
But you cannot expect the compiler to catch all your mistakes. So this was
one that it couldn't catch because in their infinite wisdom the Powers That Be
decreed that 'Map#get()' not be type parameterized. A few minutes with the
'Map' Javadocs before you refactored would've saved you some trouble. Then
you could've used Eclipse's Ctrl-Shift-G (find all references) or the
equivalent for your IDE and fixed the problem with even less effort than
letting the compiler find the error would have caused.
I think we're spoiled by how much help Java gives us to catch and prevent
error. We start whining like little brats when we reach one of those corners
that we have to sweep with our own effort.
You did the community a good service by alerting us to this particular corner.
--
Lew