@Override
    public Optional<ColumnMapper<?>> build(Type type, ConfigRegistry config) {
        return Optional.ofNullable(STRATEGIES.get(getErasedType(type)))
                .map(strategy -> strategy.apply(type, config));
    }
Column mapper factory which knows how to map Optionals:
<ul>
    <li>{@link Optional}</li>
    <li>{@link OptionalInt}</li>
    <li>{@link OptionalLong}</li>
    <li>{@link OptionalDouble}</li>
</ul>
core/src/main/java/org/jdbi/v3/core/mapper/OptionalColumnMapperFactory.java