1. Java program to generate first odd numbers then pick and display prime numbers among them.

import java.io.*;

public class OddNumber

{

     public static void main(String args[]) throws IOException

     {

           int limit;

           int b=0;

           limit = Integer.parseInt(args[0]);

           int a[]= new int[50];

           System.out.println("Odd numbers between 1 and " + limit);

           for(int i=1; i <= limit; i++)

           {

                boolean isPrime = true;

                           for(int j=2; j < i ; j++)

                           {                       

                                 if(i % j == 0)

                                 {

                                      isPrime = false;

                                      break;

                                 }

                           }

                //if the number is not divisible by 2 then it is odd

                           if( i % 2 != 0)

                           {

                           System.out.print(i + " ");

                           }

                           if(isPrime)

                           {

                                 if(i>2)   //1 is not prime and 2 is even.

                                 {

                                      a[b] =i;

                                      b++;

                                 }

                           }

           }

           System.out.println("\nPrime numbers are as follows:");

                for(int k=0;k<=b-1;k++)

                           System.out.println(a[k]);

     }

}