Java program to display prime numbers from 1 to 100 and 1 to n

class PrimeNumbers
{
   public static void main (String[] args)
   {
       int i =0;
       int num =0;
       //Empty String
       String  primeNumbers = "";

       for (i = 1; i <= 100; i++)         
       {     
          int counter=0;   
          for(num =i; num>=1; num--)
  {
             if(i%num==0)
     {
  counter = counter + 1;
     }
  }
  if (counter ==2)
  {
     //Appended the Prime number to the String
     primeNumbers = primeNumbers + i + " ";
  }
       }
       System.out.println("Prime numbers from 1 to 100 are :");
       System.out.println(primeNumbers);
   }
}


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