Post Ur Java Programs

Hi friends i have started dis forum regarding interview based......
so post ur programs which u think dat s neccessary in d basis of interview.....

FACTORIAL

import java.math.BigInteger;
public class Factorial {
public static void main(String[] args) {

//-- BigInteger solution.
BigInteger n = BigInteger.ONE;
for (int i=1; i<=20; i++) {
n = n.multiply(BigInteger.valueOf(i));
System.out.println(i + "! = " + n);
}

//-- int solution (BAD IDEA BECAUSE ONLY WORKS TO 12).
int fact = 1;
for (int i=1; i<=20; i++) {
fact = fact * i;
System.out.println(i + "! = " + fact);
}
}
}


Fibonacci

public class Fibonacci {
public static long fib(int n) {
if (n <= 1) return n;
else return fib(n-1) + fib(n-2);
}

public static void main(String[] args) {
int N = Integer.parseInt(args[0]);
for (int i = 1; i <= N; i++)
System.out.println(i + ": " + fib(i));
}

}