Exceptions - General Questions

The root class of all exceptions and errors is:

What is the output of the following program?

public class Main {
    public static void main(String[] args) {
        try {
            Integer.parseInt("12a");
        } catch (NumberFormatException e) {
            System.out.println("bad number");
        }
    }
}

Which of these is a checked exception?

What is the output of the following program?

public class Main {
    public static void main(String[] args) {
        try {
            String s = null;
            s.length();
        } catch (NullPointerException e) {
            System.out.println("NPE");
        }
    }
}

What is the output of the following program?

class Main {
    static int f() {
        try { return 1; } finally { System.out.print("F"); }
    }
    public static void main(String[] args) { System.out.println(f()); }
}