Thread: Exception Handling

Hi all, I am new to this forum so please be patient with me. I am a new programmer and I seem to be confused with the concept of exception handling. If we are to write code that would try a statement then catch the error, why wouldn't we be able to just anticipate that an error would occur and re-write the code so there wouldn't be a runtime/compile error, therefore eliminating the need of the try/catch statements? Am I missing something here? Thanks!

Well your are confusing compile time errors with run time errors. For example, if you were to accidentally forget to add a bracket for your construct:

public class test {
public test() {
}

That is a compile time error, something the compiler can realistically predict. Where-as run time errors are things that having a compiler predict would either be far too expensive (performance wise), or just down right impossible (at this time).

public class test {

public static void main(String[] args) {

try(BufferedReader br = new BufferedReader(new FileReader("file\\test.txt"))) {


}
catch(IOException ioe) { System.out.println("you see Linux power you had that file on your computer like you were supposed to, however your clients were either blocking access or didn't have that file");}


}
}

Originally Posted by LinuxPower

why wouldn't we be able to just anticipate that an error would occur and re-write the code so there wouldn't be a runtime/compile error, therefore eliminating the need of the try/catch statements? Am I missing something here? Thanks!

What code do you write to predict a hardware device fails, or the network being interrupted, or power going out, or even things like users giving bad input? The try/catch IS the way we handle these situations. You expect this thing the code is doing to work, but sometimes it just does not work out, and the code needs to respond.
For example, you go to the ATM and withdraw money, and there was no try/catch. Suppose the cash dispenser tears up a bill and fails to give out cash. The program told it to give your cash and deducts the amount from your balance leaving you with no cash. On the other hand with the try/catch, when the dispenser fails and throws the exception the program can prevent itself from adjusting your balance knowing no cash was given.

Sounds a bit more clear now. Thanks!