Program 5:

Handle various exceptions using try, catch, throw, throws, and finally. Include nested try blocks and a custom exception subclass

// Custom exception subclass
class MyException extends Exception {
    private int detail;

    MyException(int a) {
        detail = a;
    }

    public String toString() {
        return "MyException[" + detail + "]";
    }
}

public class ExceptionHandlingDemo {

    // Method that throws a custom exception
    static void compute(int a) throws MyException {
        System.out.println("Called compute(" + a + ")");
        if (a > 10)
            throw new MyException(a);
        System.out.println("Normal exit");
    }

    public static void main(String[] args) {
        try {
            // Nested try block
            try {
                int a = args.length;
                System.out.println("a = " + a);
                int b = 42 / a; // May cause ArithmeticException

                int[] c = {1};
                c[42] = 99;     // May cause ArrayIndexOutOfBoundsException

            } catch (ArithmeticException e) {
                System.out.println("Divide by 0: " + e);
            }

            compute(1);   // No exception
            compute(20);  // Will throw MyException

        } catch (MyException e) {
            System.out.println("Caught: " + e);
        } finally {
            System.out.println("Inside finally block");
        }
    }
}

Updates

try {
    int a = args.length;
    System.out.println("a = " + a);

    try {
        int b = 42 / a;
    } catch (ArithmeticException e) {
        System.out.println("Divide by 0: " + e);
    }

    try {
        int[] c = {1};
        c[42] = 99;
    } catch (ArrayIndexOutOfBoundsException e) {
        System.out.println("Array index error: " + e);
    }

    compute(1);
    compute(20);

} catch (MyException e) {
    System.out.println("Caught: " + e);
} finally {
    System.out.println("Inside finally block");
}