SumPrimeNonPrime

import java.util.Scanner;

public class SumPrimeNonPrime {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int primeSum = 0;
        int nonPrimeSum = 0;

        /**
         * PRIME NUMBER - a number that is divisible only by itself and 1 (e.g. 2, 3, 5, 7, 11).
         * NON PRIME NUMBER - non-prime numbers are divisible by more than two numbers.
         */

        String command = scanner.nextLine();
        while(!command.equals("stop")) {
            int currentNum = Integer.parseInt(command);

            // check for negative number
            if(currentNum < 0){
                System.out.println("Number is negative.");
                command = scanner.nextLine();
                continue;
            }

            // save count of dividers
            int dividersCount = 0;
            for (int i = 1; i <= currentNum; i++) {
                // check if num is divisible
                if(currentNum % i == 0) {
                    dividersCount++;
                }
            }

            // check if number is prime or non prime
            if(dividersCount > 2) {
                nonPrimeSum = nonPrimeSum + currentNum;
            } else{
                primeSum = primeSum + currentNum;
            }

            command = scanner.nextLine();
        }

        System.out.printf("Sum of all prime numbers is: %d%n", primeSum);
        System.out.printf("Sum of all non prime numbers is: %d", nonPrimeSum);

    }
}