leetcode 179 largest number

public static String (int[] nums) {
	String[] s = new String[nums.length];
	for (int i = 0; i < nums.length; i++) s[i] = String.valueOf(nums[i]);
	Arrays.sort(s, (b, a) -> (a.concat(b).compareTo(b.concat(a))));
	StringBuffer result = new StringBuffer("");
	for (String num : s) result.append(num);
	return result.substring(0, 1).equals("0") ? "0" : result.toString();
}

public String largestNumber2(int[] nums) {
	String result = Arrays
			.stream(nums)
			.mapToObj(Integer::toString)
			.sorted((b, a) -> (a.concat(b).compareTo(b.concat(a))))
			.collect(Collectors.joining());
	return result.charAt(0) == '0' ? "0" : result;
}