How to call a method that throws an exception in catch block?

Question

I am trying to have an HandleException method that can handles various exceptions.

The problem is, my function returns a value. But if I use HandleException in my catch block, Java complains that the function does not return a value even though my HandleException always throw an exception.

What is a good way to fix this? Thanks!

Here is a sample code.

public class MyException {

    static int foo(int num) throws Exception {
        try {
            return bar(num);
        } catch (Exception e) {
            handleException(); 
        //    throw new Exception("Exception in foo", e);
        }
    }

    static int bar(int num) throws IllegalArgumentException {
        if (num < 0) {
            throw new IllegalArgumentException("Num less than 0");
        }
        return num;
    }

    static void handleException(Exception e) throws Exception {
        System.err.println("Handling Exception: " + e);
        throw new Exception(e);
    }

    public static void main(String[] args) throws Exception {
        int value = foo(-1);
    }
}

In my original class, I have lot of methods that have this format.

try {
    ...
} catch (Exception1) {
    Log exception
    throw appropriate exception
} catch (Exception2) {
    Log exception
    throw appropriate exception
}

I am trying to comeup with a cleaner way to write the catch blocks.

Answer 1

This is because the exception that was thrown on handleException is already caught by the catch block of the foo method. Thus the foo method no longer throws an Exception making the catch block return nothing. So if the bar method throws an exception it will go to the catch block but since the catch block is not returning anyting, Java executes the lines after the catch block but when it reaches the end it throws an error that "the method must return a result of type int" since you do not have a return statement.

You should change this part.

public class MyException {

    static int foo(int num) throws Exception {
        try {
            return bar(num);
        } catch (Exception e) {
            throw handleException(e); // this will throw the exception from the handleException
        //    throw new Exception("Exception in foo", e);
        }
    }

    static int bar(int num) throws IllegalArgumentException {
        if (num < 0) {
            throw new IllegalArgumentException("Num less than 0");
        }
        return num;
    }

    // This method now returns an exception, instead of throwing an exception
    static Exception handleException(Exception e) {
        System.err.println("Handling Exception: " + e);
        return new Exception(e);
    }

    public static void main(String[] args) throws Exception {
        int value = foo(-1);
    }
}