Xacper

import java.math.BigInteger;

class DoubleFactorial {
    public static BigInteger calcDoubleFactorial(int n) {
        if (n == 0 || n == 1 || n < 0) {
            return BigInteger.ONE;
        }
        BigInteger res = BigInteger.ONE;
        for (BigInteger i = BigInteger.valueOf(n); !i.equals(BigInteger.ZERO) ||
                !i.equals(BigInteger.ZERO.divide(BigInteger.ONE)); i = i.subtract(BigInteger.TWO)) {

Xacper

package machine;

import java.util.Scanner;


public class Main extends Operation {
    public static void main(String[] args) {
        boolean loop = true;
        Scanner userInput = new Scanner(System.in);
        while (loop) {

Xacper

package contacts;

import java.util.ArrayList;

class Contacts {
    static final String pattern = "^\\+?(\\(\\w+\\)|\\w+[ -]\\(\\w{2,}\\)|\\w+)([ -]\\w{2,})*";
    private static final ArrayList<String> firstname = new ArrayList<>();
    private static final ArrayList<String> surname = new ArrayList<>();
    private static final ArrayList<String> numbers = new ArrayList<>();

Xacper

package contacts;

import java.util.ArrayList;

class Contacts {
    static final String pattern = "^\\+?(\\(\\w+\\)|\\w+[ -]\\(\\w{2,}\\)|\\w+)([ -]\\w{2,})*";
    private static final ArrayList<String> firstname = new ArrayList<>();
    private static final ArrayList<String> surname = new ArrayList<>();
    private static final ArrayList<String> numbers = new ArrayList<>();