ProgBasics07Nested-Loops-Y07sumPrimeNonPrime

import java.util.Scanner;

public class Y07sumPrimeNonPrime {
        public static void main(String[] args) {
            Scanner scanner = new Scanner(System.in);

            boolean nonPrimeNum = false;
            int i = 2;
            int primeNum = 0;
            int nonPrime = 0;

            while (true) {
                String command = scanner.nextLine();

                if (command.equals("stop")) {
                    break;
                }
                int num = Integer.parseInt(command);

                if (num < 0) {
                    System.out.println("Number is negative.");
                } else {
                    i = 2;

                    while (i <= num / 2) {
                        // condition for nonprime number
                        if (num % i == 0) {
                            nonPrimeNum = true;
                        }
                        ++i;
                    }
                    if (num == 1 || num == 0) {
                        nonPrime += num;
                        continue;
                    }
                    if (!nonPrimeNum) {
                        primeNum += num;
                    } else {
                        nonPrime += num;
                        nonPrimeNum = false;
                    }
                }
            }
            System.out.printf("Sum of all prime numbers is: %d%n", primeNum);
            System.out.printf("Sum of all non prime numbers is: %d", nonPrime);
        }
    }