把数组排成最小的数

import java.util.ArrayList;
import java.util.Arrays;
import java.util.stream.Collectors;
public class Solution {
    public String PrintMinNumber(int [] numbers) {
        String res = Arrays.stream(numbers)
                .mapToObj(Integer::toString)
                .sorted((a, b) -> (a+b).compareTo(b+a))
                .collect(Collectors.joining());
        return res;
    }
}