用流来处理，两行代码

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
public class Solution {
    public String PrintMinNumber(int [] numbers) {
        if (numbers == null || numbers.length == 0) return "";
        return Arrays.stream(numbers).parallel().mapToObj(String::valueOf).sorted((s1, s2) -> (s1.concat(s2).compareTo(s2.concat(s1)))).reduce("",String::concat);

    }
}