方法中的空字符串返回语句，这仅仅是出于名义目的还是可以改进？

此代码删除字符串参数中的第一个“ abc”，并返回结果字符串。

I'm just confused because I'm just returning an empty string because I wrote String instead of void. I would have used System.out.println(); along with break; if I wrote void but I just didn't because I used it in an exercise and it said bad code(even though the results are same). Would be glad if you have any opinions. This is my code below;

public static String abc(String str) {
    int i = 0;
    while(i < str.length()-2) {
        if (str.substring(i, i+3).equals("abc")) {
            return str.substring(0, i) + str.substring(i+3);
        } else {
            if (i == str.length()-3) {
                return str;
            }
        } i++;
    } return "";