HappyNumber v2

import java.util.Scanner;
import java.util.Vector;


 class HappyNumber
{

	static int squareSum(int n)
	{
		if (n == 0)
		{
			return 0;
		}

		else
		{
			int digit = n % 10;
			return (digit * digit + squareSum(n / 10));
		}
	}


	public static void main (String[] args)
	{
		Vector<Integer> v = new Vector<>(1);

		Scanner ui = new Scanner(System.in);
		int userNumber = 0;
		int firstNumber = 0; // so program correctly prints correct first given number

		do // only allows positive int as an input
		{
			System.out.println("Please enter a positive integer.");
			while (!ui.hasNextInt())
			{
				System.out.println("Invalid input. Please enter a positive integer.");
				ui.next();
			}

		userNumber = ui.nextInt();
		firstNumber = userNumber;

		}
		while (userNumber <= 0);

		int a = 0;	// initializing loop values
		int b = 0;
		boolean dupe = false;

		do
		{
			a = userNumber;
			b = squareSum(a);

			v.add(a);  // adding the value to the vector to print each intermediate number

			userNumber = b;

			// loop for checking duplicates

			for (int j = 0; j < v.size(); j++)
			{
				for (int k = j + 1; k < v.size(); k++)
				{
					if (k !=j && v.get(k) == v.get(j))
					{
						dupe = true;
					}
				}
			}

			if (b == a)
			{
				break;
			}
		}

		while(dupe == false);

		System.out.println(v);

		if (dupe == true)
		{
			System.out.println(firstNumber + " is unhappy.");
		}

		else
		{
			System.out.println(firstNumber + " is happy.");
		}


		ui.close();

	}

}