boolean (@NotNull CharSequence argument) { if (argument.length() == 0) { return true; } for (int i = 0; i < argument.length(); i++) { char c = argument.charAt(i); if (!Character.isAlphabetic(c) && !Character.isDigit(c) && !StringUtil.containsChar(SHELL_WHITELIST_CHARACTERS, c)) { return true; } } return false; }