Why R is not being printed ? why the output is PQST?

Question

Here's my code. Here PQRST should be the output but R is not printed. I don't understand why ?

class Validator{
    public int[] studentId = { 101, 102, 103 };

    public void validateStudent(int id) {
        try {
            for (int index = 0; index <= studentId.length; index++) {
                if (id == studentId[index])
                    System.out.println("P");
            }
        } finally {
            System.out.println("Q");
        }
    }
}


public class Tester {
    public static void main(String[] args) {
        Validator validator = new Validator();
        try {
            validator.validateStudent(101);
            System.out.print("R");
        } catch (ArrayIndexOutOfBoundsException e) {
            System.out.println("S");
        } finally {
            System.out.println("T");
        }
    }
}

Answer 1

The problem is that the validateStudent method ends with an ArrayIndexOutOfBoundsException exception, and therefore the System.out.print ("R"); statement does not execute. When the exception happens.

I would probably try to solve this problem a little differently and not with exceptions, which in my opinion are quite complicated in terms of logic and processing. It simply slows down the program that could be more simple.

Answer 2

Your code is currently throwing an ArrayIndexOutOfBoundsException. Because you exceed the length of the array. This

for (int index = 0; index <= studentId.length; index++) {

should be

for (int index = 0; index < studentId.length; index++) {

But then S will not be printed (because it won't throw an Exception).

Today is an excellent day to learn how to use a debugger.