public final boolean isBlankInput() {
        for (int i = 0;; ++i) {
            char chLocal = buf[i];
            if (chLocal == EOI) {
                token = JSONToken.EOF;
                break;
            }

            if (!isWhitespace(chLocal)) {
                return false;
            }
        }

        return true;
    }
The value of a literal token, recorded as a string. For integers, leading 0x and 'l' suffixes are suppressed.
src/main/java/com/alibaba/fastjson/parser/JSONReaderScanner.java