On suns site, there is an open bug for operator overloading. Many people have pointed out that Java has one special case of operator overloading (String + String), so why not allow the programmer to overload operators?
Operator overloading would become especially useful when the addition of the units and measures API, or other custom libraries that are similar. It becomes especially useful when trying to avoid primitive obsession, and create numeric-like types.
Imagine this case:
Speed s = endDistance.minus(startDistance).divide(duration);
could be simplified to
Speed s = (endDistance - startDistance) / duration;
This of course is a simple example, and yet one that I would love to use in some of my existing code-bases.
Another use case would be a cleaner syntax for lists/maps:
myMap["Hey"] = "There"; System.out.println(myList);
And hey, what about a special case for compareTo? Although it might be too dangerous to overload =/==, I could see overloading <, > <=, and >=. It might be nice to add a couple of operators to the mix. I’m officially suggesting “#” for concatenation. Maybe “:=” for shortand to .equals().