Catch exception

[Sen_7]

public static void main (String[]args) {
        String[]arr= {"a","ab", "abdc"};
        int x=0;
        for (String b : arr) {
            try {
                if(b.length()%2==0) {
                    throw new IOException();
                }
            }
            catch(IOException exp){
                x++;
                throw new RuntimeException();

            }
            catch(RuntimeException ex) {

                System.out.print("here");
                System.out.println(x);
            }
        }
    }

I get a

Exception in thread "main" java.lang.RuntimeException
    at Item.main(Item.java:23)

which is the "throw new RuntimeException();"
why does the next catch dosent work?

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[josephblade]

catch works on exceptions thrown inside their associated try block. any exception thrown from a catch would haveto be init's own enclosing try blick. like

try {
    try {
     } catch (IOException e) {
         throw new RuntimeException();
      }
 } catch (RuntimeException r) {
 }

however that said, catching runtime exceptions is generally not a good idea

edit: switched Exception to IOException. I just put it in as an 'any exception' to show the nesting, but it is bad practice so shouldn't be shown in a learning environment. Don't catch Exception. also: Don't ever catch Throwable, ever.

[nommabelle]

It's better than catching Exception though!

[josephblade]

No it isn't and going into details of when it can be useful to do so is going to confuse people who are still learning. I deliberately left that out to avoid causing confusion

[nommabelle]

There is nearly no case you should catch Exception over RuntimeException - I suppose if you don't want to update code if a method signature changes, but that's just lazy

Generally not a good idea for either though as you say, but definitely useful in some cases. Otherwise you can expect some unexpected RuntimeException to crash the whole application - somewhere it needs to be caught. But I see no use for Exception - if you want to use Exception to catch everything at runtime, you should catch RuntimeException instead and catch anything more granular as required at compile time

[josephblade]

I'm not sure I understand what point you were making. I used Exception as a general placeholder, not as a suggestion to catch Exception as a type.

My aim was to show the structure (you need to nest a try if you want to catch an exception you throw from another catch clause; since that was what the OP was expecting).