在Java中，最小值总是显示为0

import java.util.Scanner;
import java.util.List;
import java.util.Arrays;
import java.util.*;



public class Exercise16 {
    public static void main(String[] args) {
        System.out.println("Please enter a sequence of positive integers");
        Scanner user_input = new Scanner(System.in);
        String user_string = user_input.nextLine();
        boolean hasNegativeOne = user_string.contains("-1");

        if (hasNegativeOne){
            String[] sequence = user_string.split(" ");

            int[] numbers = new int[sequence.length];

            for (int i = 0; i < sequence.length;i++) {
                numbers[i] = Integer.parseInt(sequence[i]);
            }


        // Method for getting the maximum value
            int max_value = 0;
            for(int i=0; i<numbers.length; i++){
                if (numbers[i] > max_value){
                    max_value = numbers[i];
                }
            }

        // Method for getting the minimum value
            int min_value = 0;
            for(int i=0; i<numbers.length; i++){
                if (numbers[i] < min_value){
                    min_value = numbers[i];
                }
            }


            System.out.println("The maximum value is: " +max_value);
            System.out.println("The minimum value is: " +min_value);


        }

    }
}
import java.util.Scanner;
import java.util.List