### Question:
CertificateSelector { public CertificateSelector<T> bySubjectOrganization(final String organization) { Preconditions.checkArgument( StringUtils.isNotEmpty(organization), "organization cannot be null or empty." ); setFieldValue(Certificate.SUBJECT_ORGANIZATION_FIELD, organization); return this; } CertificateSelector(
            final CertificateManager certificateManager,
            final Class<T> certificateClass);  CertificateSelector(
            final CertificateManager certificateManager,
            final Class<T> certificateClass, final boolean excludeArchivedCertificates); CertificateSelector<T> byEntityId(final UUID uuid); CertificateSelector<T> byHashCode(final int certificateHash); CertificateSelector<T> bySerialNumber(final BigInteger serialNumber); CertificateSelector<T> byHolderSerialNumber(final BigInteger holderSerialNumber); CertificateSelector<T> byIssuer(final String issuer); CertificateSelector<T> bySubject(final String subject); CertificateSelector<T> byIssuerOrganization(final String organization); CertificateSelector<T> bySubjectOrganization(final String organization); CertificateSelector<T> byEncodedPublicKey(final byte[] encodedPublicKey); CertificateSelector<T> byPublicKeyModulus(final BigInteger publicKeyModulus); T getCertificate(); Set<T> getCertificates(); X509Certificate getX509Certificate(); Set<X509Certificate> getX509Certificates(); KeyStore getKeyStore(); Class<T> getCertificateClass(); CertificateSelector<T> includeArchived();  }### Answer:
@Test(expectedExceptions = IllegalArgumentException.class) public void testNullBySubjectOrganization() { CertificateAuthorityCredential.select(certMan).bySubjectOrganization(null); }