public static String validateSubject(String claimName, String claimValue) throws ValidateException {
        return validateString(claimName, claimValue);
    }
Validates that the given claim value is valid, where <i>invalid</i> means <i>any</i> of
the following:

<ul>
    <li><code>null</code></li>
    <li>Zero length</li>
    <li>Whitespace only</li>
</ul>

@param claimName  Name of the claim
@param claimValue Name of the subject

@return Trimmed version of the <code>claimValue</code> parameter

@throws ValidateException Thrown if the value is <code>null</code>, empty, or whitespace only
clients/src/main/java/org/apache/kafka/common/security/oauthbearer/internals/secured/ClaimValidationUtils.java