public abstract ImmutableSet<String> objectClasses();
@Test
    void objectClasses() {
        final LDAPEntry entry = LDAPEntry.builder()
                .dn("cn=jane,ou=people,dc=example,dc=com")
                .base64UniqueId(Base64.encode("unique-id"))
                .addAttribute("foo", "bar")
                .build();

        assertThat(entry.objectClasses()).isEmpty();

        final LDAPEntry entry2 = LDAPEntry.builder()
                .dn("cn=jane,ou=people,dc=example,dc=com")
                .base64UniqueId(Base64.encode("unique-id"))
                .addAttribute("foo", "bar")
                .objectClasses(Collections.singleton("inetOrgPerson"))
                .build();

        assertThat(entry2.objectClasses()).containsExactlyInAnyOrder("inetOrgPerson");
    }