All conditions except - "3. After entering -1, the program must correctly terminate."

Question about the task

Under discussion

The code apparently satisfies all conditions except "3. After entering -1, the program must correctly terminate." Though with "Run (without verification)", I get the required results for all the combinations listed..

Use the keyboard to enter numbers, and then calculate the arithmetic mean.
If the user enters -1, display the arithmetic mean of all entered numbers and end the program.
-1 should not be included in the calculation.

Here are some examples:
a) if you enter the numbers
1
2
2
4
5
-1
then we display
2.8

b) if you enter the numbers
4
3
2
1
-1
then we display
2.5

Hint: one of the solutions to this problem uses the following construct:

while (true) {
    int number = read the number;
    if (check whether the number is -1)
        break;
}

Requirements:

The program must read data from the keyboard.
The program should display data on the screen.
After entering -1, the program must correctly terminate.
If you sequentially enter the numbers 1, 2, 2, 4, 5 and -1, the program should display 2.8.
If you sequentially enter the numbers -100, 0, 100, and -1, the program should display 0.0.
If you sequentially enter the numbers 1 and -1, the program should display 1.0.
The displayed result should match the task conditions for any input data.

package com.codegym.task.task05.task0507; import java.io.*; /* Arithmetic mean */ public class Solution { public static void main(String[] args) throws Exception { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String s = reader.readLine(); int ss = Integer.parseInt(s); int sw = 0; int count = 0; Double mean = 0.0; boolean isExit = false; while (!isExit) { sw = sw + ss; s = reader.readLine(); ss = Integer.parseInt(s); count++; isExit = s.equals("-1"); } mean = (double)sw/count; System.out.println(mean); } }