why does the use of "System.err.println" break a do/while loop?

import java.util.Scanner;

public class Main {

private static Scanner input = new Scanner(System.in);    private static final String INPUT_ERROR1 = "Weight can not be negative or zero!";  private static final String INPUT_ERRORe = "Input can not contain non-numeric characters";      public static void main(String[] args) {      double lbs, inches, meters, kgs, bmi;      String classification;        System.out.println("Calculate BMI");      lbs = inputWeight();    }    public static double inputWeight() {      double weight = 0.00;      do {          System.out.print("Enter weight(lbs): ");          String weightInput = input.nextLine();          try {              weight = Double.parseDouble(weightInput);              if (weight <= 0) {                  System.out.println(INPUT_ERROR1);              }          } catch (Exception e) {              System.err.println(INPUT_ERRORe);          }      } while (weight <= 0);      return weight;  }  

} In the above code replacing the the current println lines with System.err.println lines breaks my do/while loop. Why is this?

https://stackoverflow.com/questions/66978226/why-does-the-use-of-system-err-println-break-a-do-while-loop April 07, 2021 at 08:47AM