static int getNumberOfPrimes(int N) {        int n = N+1;//to include 0 as the first number for easy index operations later        final boolean a[] = new boolean[n]; //Initialized to null by default.         Arrays.fill(a, true);                  a[0] = false;         a[1] = false;         for (int i = 2; i < n / 2; ++i)         {             if (a[i])             {                 for (int j = i + i; j < n; j += i)                     a[j] = false;            }         }                 int count = 0;for(int i = 2;i<n;++i)        {            if(a[i])            {                //System.out.print(i+",");                ++count;            }        }        return count;    }