В IntelliJ IDEA все работает
package com.javarush.task.task04.task0420;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
int a = Integer.parseInt(reader.readLine());
int b = Integer.parseInt(reader.readLine());
int c = Integer.parseInt(reader.readLine());
if (a>b){
if (b>c){
System.out.println(a+" "+b+" "+c);
}
else System.out.println(a+" "+c+" "+b);
}
else {
if (a>c) System.out.println(b+" "+a+" "+c);
else System.out.println(b+" "+c+" "+a);
}
}
}