Checked exceptions sucks

    private ResultSetHandler<ExternalMapping> emHandler(Optional<Provider> p0) {
        return rs -> ExternalMapping.builder()
            .id(rs.getLong("id"))
            .provider(p0.isPresent() ? // let's get rid of this conditional
                p0.get() :
                Provider.fromInt(rs.getInt("provider")))
            .isDeleted(rs.getBoolean("isDeleted"))
            .entityUuid(UUID.fromString(rs.getString("entityUuid")))
            .externalId(rs.getString("externalId"))
            .entityType(EntityType.fromInt(rs.getInt("entityType")))
            .createdAt(rs.getTimestamp("createdAt").toInstant())
            .updatedAt(rs.getTimestamp("updatedAt").toInstant())
            .build()
    }
// aaand...
    private ResultSetHandler<ExternalMapping> emHandler(Optional<Provider> p0) {
        return rs -> ExternalMapping.builder()
            .id(rs.getLong("id"))
            // OMG, sooooooooooooooo ugly
            .provider(p0.orElseGet(() -> {
                try {
                    return Provider.fromInt(rs.getInt("provider"));
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }))
            .isDeleted(rs.getBoolean("isDeleted"))
            .entityUuid(UUID.fromString(rs.getString("entityUuid")))
            .externalId(rs.getString("externalId"))
            .entityType(EntityType.fromInt(rs.getInt("entityType")))
            .createdAt(rs.getTimestamp("createdAt").toInstant())
            .updatedAt(rs.getTimestamp("updatedAt").toInstant())
            .build()
    }

// however Callable<T> helps us here:
    private static <T> Supplier<T> rethrow(Callable<T> callable) {
        return () -> {
            try {
                return callable.call();
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        };
    }

    // with this we can polish the handler:
    private ResultSetHandler<ExternalMapping> emHandler(Optional<Provider> p0) {
        return rs -> ExternalMapping.builder()
            .id(rs.getLong("id"))
            // looks better now
            .provider(p0.orElseGet(rethrow(() -> Provider.fromInt(rs.getInt("provider")))))
            .isDeleted(rs.getBoolean("isDeleted"))
            .entityUuid(UUID.fromString(rs.getString("entityUuid")))
            .externalId(rs.getString("externalId"))
            .entityType(EntityType.fromInt(rs.getInt("entityType")))
            .createdAt(rs.getTimestamp("createdAt").toInstant())
            .updatedAt(rs.getTimestamp("updatedAt").toInstant())
            .build();
    }