Почему не выполняется последнее условие?

package com.javarush.task.pro.task05.task0504;

/*
Объединяем массивы
*/

public class Solution {
    public static int[] firstArray = new int[]{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    public static int[] secondArray = new int[]{10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
    public static int[] resultArray;

    public static void main(String[] args) {
        //напишите тут ваш код
        resultArray = new int[firstArray.length+secondArray.length];
        int number = firstArray.length- secondArray.length;
        int number2 = firstArray.length;
        if(number<firstArray.length){
            while (number<firstArray.length){
                resultArray[number] = firstArray[number];
                number++;
            }
        }
        if(number>=secondArray.length && number<= resultArray.length){
            while (number2< resultArray.length){
                resultArray[number2] = secondArray[number2-firstArray.length];
                number2++;
                number++;
            }
        }

        for (int i = 0; i < resultArray.length; i++) {
            System.out.print(resultArray[i] + ", ");
        }
    }
}

resultArray[number] = firstArray[number];