Java join paths into full file path

public static String join(String... paths) {
    if (paths == null || paths.length == 0) {
        return "";
    }

    StringBuilder sb = new StringBuilder();
    sb.append(paths[0]);
    for (int i = 1; i < paths.length; i++) {
        sb.append(File.separatorChar).append(paths[i]);
    }

    return sb.toString();
}