private String listJsonText(String value) {
        if (value.length() <= 1)
            return "[]";
        String delimiter;
        String unescapedDelimiterChar = value.substring(0, 1);
        switch (unescapedDelimiterChar) {
            case "\\":
            case ".":
            case "[":
            case "(":
            case "{":
            case "|":
            case "^":
            case "$":
                delimiter = "\\" + unescapedDelimiterChar;
                break;
            default:
                delimiter = unescapedDelimiterChar;
                break;
        }
        String listText = value.substring(1);
        String[] elements = listText.split(delimiter);
        StringBuilder sb = new StringBuilder();
        for (String element : elements) {
            sb.append(sb.length() == 0 ? '[' : ',');
            sb.append('"').append(escape(element)).append('"');
        }
        if (listText.startsWith(unescapedDelimiterChar) || listText.endsWith(unescapedDelimiterChar)
                || listText.contains(unescapedDelimiterChar + unescapedDelimiterChar))
            sb.append(",\"\"");
        return sb.append(']').toString();
    }
Add and validate all the configured extensions.
 Token keys, apart from passing regex validation, must not be equal to the reserved key {@link OAuthBearerClientInitialResponse#AUTH_KEY}
clients/src/main/java/org/apache/kafka/common/security/oauthbearer/internals/unsecured/OAuthBearerUnsecuredLoginCallbackHandler.java