public Long validateLong(String name) {
        return validateLong(name, true);
    }
Validates that, if a value is supplied, is a value that:

<li>
    <ul>is an Integer</ul>
    <ul>has a value that is not less than the provided minimum value</ul>
</li>

If the value is null or an empty string, it is assumed to be an "empty" value and thus
ignored. Any whitespace is trimmed off of the beginning and end.
clients/src/main/java/org/apache/kafka/common/security/oauthbearer/internals/secured/ConfigurationUtils.java