[java] Remove trailing comma from comma-separated string

This method is in BalusC's StringUtil class. his blog

i use it very often and will trim any string of any value:

/**
 * Trim the given string with the given trim value.
 * @param string The string to be trimmed.
 * @param trim The value to trim the given string off.
 * @return The trimmed string.
 */
public static String trim(String string, String trim) {
    if (string == null) {
        return null;
    }

    if (trim.length() == 0) {
        return string;
    }

    int start = 0;
    int end = string.length();
    int length = trim.length();

    while (start + length <= end && string.substring(
            start, start + length).equals(trim)) {
        start += length;
    }
    while (start + length <= end && string.substring(
            end - length, end).equals(trim)) {
        end -= length;
    }

    return string.substring(start, end);
}

ex:

trim("1, 2, 3, ", ", ");