Try doing that in a code base without checked exceptions. You just created 100s or 1000s of unrecognised errors in other code without realising it. The problem is not the checked exception. The problem is you changed something 100s or 1000s of things are relying on to add a new failure mode.
> Checked exceptions lead to terrible error handling and hiding bugs/system problems. instead of letting exceptions bubble up - java coders almost always write code that either swallows or simply logs ....
Well, I agree up to a point. But that is much to do with how tedious and verbose the error handling itself is which is more about the language than the concept of checked exceptions.
> they lead to bugs. I very rarely see anyone handle the statement/resultset handling of JDBC code correctly.
see above
> 5) if they are such a good idea, why does no other language ever created has them?
Well, you can also say, if they are such a bad idea, how come one of the world's most popular and used language builds them into all its core APIs? They can't be that terrible or Java would never have got so popular ....