Calculating Euler's number e with BigDecimal

 
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;

public class Main {
  final static int LASTITER = 17;

  public static void main(String[] args) {
    MathContext mc = new MathContext(100, RoundingMode.HALF_UP);
    BigDecimal result = BigDecimal.ZERO;
    for (int i = 0; i <= LASTITER; i++) {
      BigDecimal factorial = factorial(new BigDecimal(i));
      BigDecimal res = BigDecimal.ONE.divide(factorial, mc);
      result = result.add(res);
    }
    System.out.println(result);
  }

  public static BigDecimal factorial(BigDecimal n) {
    if (n.equals(BigDecimal.ZERO))
      return BigDecimal.ONE;
    else
      return n.multiply(factorial(n.subtract(BigDecimal.ONE)));
  }

}