Help, I can't see where is the mistake
package com.codegym.task.task09.task0930;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
/*
Task about algorithms
*/
public class Solution {
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
ArrayList<String> list = new ArrayList<String>();
while (true) {
String s = reader.readLine();
if (s.isEmpty()) break;
list.add(s);
}
String[] array = list.toArray(new String[list.size()]);
sort(array);
for (String x : array) {
System.out.println(x);
}
}
public static void sort(String[] array) {
// write your code here
String[] numbers = new String[10];
String[] strings = new String[10];
int q=0;
for(int i=0; i<array.length; i++){
if (isNumber(array[i])){
numbers[q] = array[i];
q++;
}
}
int p=0;
for(int i=0; i<array.length; i++){
if (isNumber(array[i])==false){
strings[p] = array[i];
p++;
}
}
for(int j=0; j<strings.length; j++){
for(int i=0; i<strings.length;i++){
if (isGreaterThan(strings[i], strings[j])){
String str = strings[i];
strings[j]=strings[i];
strings[i]=str;
}
}
}
for(int j=0; j<numbers.length; j++){
for(int i=0; i<numbers.length;i++){
if (isGreaterThan(numbers[j], numbers[i])==false){
String str = numbers[i];
numbers[j]=numbers[i];
numbers[i]=str;
}
}
}
int a=0;
for (int i=0; i<array.length;i++){
array[i]=strings[a];
i++;
array[i]=numbers[a];
a++;
}
}
// String comparison method: 'a' is greater than 'b'
public static boolean isGreaterThan(String a, String b) {
return a.compareTo(b) > 0;
}
// Is the passed string a number?
public static boolean isNumber(String s) {
if (s.length() == 0) return false;
char[] chars = s.toCharArray();
for (int i = 0; i < chars.length; i++) {
char c = chars[i];
if ((i != 0 && c == '-') // The string contains a hyphen
|| (!Character.isDigit(c) && c != '-') // or is not a number and doesn't start with a hyphen
|| (i == 0 && c == '-' && chars.length == 1)) // or is a single hyphen
{
return false;
}
}
return true;
}
}