// In the interface
PrimeGenerator pg = new PrimeGenerator(100) // Construct something to generate primes up to 100

while (pg.hasNextPrime())
{
    System.out.println(pg.nextPrime())
}

// Generator for Fibonacci numbers
public class FibonacciGenerator
{
   private int fold1 = 0;
   private int fold2 = 1;
   private int fnew = 0;

   public FibonacciGenerator()
   {
   }
   public int nextNumber()
   {
      fnew = fold1 + fold2;
      fold2 = fold1;
      fold1 = fnew;
      return fnew;
   }
}

import java.util.Scanner;

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

      System.out.println("Enter n:");
      int n = in.nextInt();

      FibonacciGenerator fg = new FibonacciGenerator();

      for (int i = 1; i <= n; i++)
         System.out.println(fg.nextNumber());
   }
}