Why FileNotFoundException is CheckedException?

Question

I know FileNotFound is Checked Exception but though it is, only during the Run time this exception will occur.It is more like Arithmetic Exception(Unchecked).

Whether it is checked or unchecked the exception will happen only during runtime.

My Question is why we call the FileNotFound/IO/DB related stuffs as Checked Exception?

Please share me your valuable thoughts :)

Answer 1

Exceptions always encountered at runtime only, Difference is made when a exception is handled.

Checked or unchecked means whether it is forced to handle at compile time or it will only be identified when it is encountered at runtime.

If an exception is checked means compiler has way to identify whether the exception can occur or not. and whenever you compile it, you will be forced to handle a checked exception and by doing this chances of runtime exceptions will be reduced.

During file handling, compiler doesn't check whether file is present or not, it just check whether you have handled fileNotFoundException or not, because once you are dealing with a file chances of encountering this exception is very high and you should handle it in your code. for arithmetic Exception there is not way to find it during compile time. and thus it is left unchecked.

Answer 2

NullPointerException or ArithmeticException usually shouldn't happen in a finished, correct program. You can handle those just with checking before with if to see if you divide by 0 or an object is null and then you are sure this Exception will not be thrown. Every time handling those Exceptions can make the code less readable.

Now you could argue that you could do the same for FileNotFoundException by just checking if the file exists before doing anything. But many constructors or methods that expect a File also support String from which the file is created then. I guess it is a question of where you draw the line, if you always only have the File method and never also support String then I would have added it to the unchecked ones too I think.

In other words: if a FileNotFoundException is thrown then it can be the desired behaviour and drive the flow of your program, but NullPoinerException really shouldn't be used for that.