best way to check if a number is prime java code example

Example 1: making list of prime numbers java

Now let’s see print first 10 prime numbers in java.

public class FirstTenPrimeNumbers
{
   public static void main(String[] args) 
   {
      int count = 0, number = 0, a = 1, b = 1;  
      while(number < 10)  
      {  
         b = 1;  
         count = 0;  
         while(b <= a)  
         {  
            if(a%b == 0)  
                count++;  
            b++;
         }  
         if(count == 2)  
         {  
            System.out.printf("%d ", a);  
            number++;  
         }  
         a++;  
      }
   }
}

Example 2: how to check if number prime in java

public class PrimeNumberInJava
{
   public static void main(String[] args)
   {
      int a, b = 0, flag = 0;
      int number = 17;
      b = number / 2;
      if(number == 0 || number == 1)
      {
         System.out.println(number + " is not prime number");
      }
      else
      {
         for(a = 2; a <= b; a++)
         {
            if(number % a == 0)
            {
               System.out.println(number + " is not prime number.");
               flag = 1;
               break;
            }
         }
         if(flag == 0)
         {
            System.out.println(number + " is prime number.");
         }
      }
   }
}