Composite Magic Number Range

/**
 * This program inputs two numbers and prints the composite magic numbers in the entered range (Start and end included).
 * For more information, please visit: https://goo.gl/XsZQ4p .
 */
import java.util.Scanner;
public class Magic_Composite_Range
{
    static boolean isComposite(int num)
    {
        if(num == 2)
            return false;

        int i,flag = 0;
        for(i=2;i<num;i++)
        {
            if(num%i==0)
            {
                flag=1;
                break;
            }
        }

        if(flag == 1)
            return true;
        else
            return false;
    }

    static int digitSum(int num)
    {
        String a = Integer.toString(num);
        int i,x,sum=0;
        for(i=0;i<a.length();i++)
        {
            x = Character.getNumericValue(a.charAt(i));
            sum += x;
        }

        return sum;
    }

    static boolean isMagic(int num)
    {
        int sum = 0;
        sum = digitSum(num);
        while(sum > 9)  //Since any number <=9 can't have the sum of 1 unless it is 1 itself.
        {
            sum = digitSum(sum); //Finding the eventual sum.
        }
        if(sum == 1)
            return true;
        else
            return false;
    }

    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("Please enter the lower limit.");
        int start = sc.nextInt();
        System.out.println("Please enter the upper limit.");
        int end = sc.nextInt();
        System.out.println();

        if(start<end)
        {
            int i,ct=0;
            for(i=start;i<=end;i++)
            {
                boolean check1 = isComposite(i);
                boolean check2 = isMagic(i);
                if(check1 && check2)
                {
                    System.out.print(i+" | ");
                    ct++;
                }
            }
            System.out.println("\nNumber of composite magic numbers between "+start+" and "+end+" = "+ct);
        }

        else
            System.out.println("Incorrect input. The lower limit must be lesser than the upper limit.");

        sc.close();
    }
}