---
title: "Configuration"
description: "Configuration — Java BabelQueue SDK (1.x)."
source: https://babelqueue.com/docs/babelqueue-java/1.x/configuration/
updated: 2026-06-06T00:00:00.000Z
---

# Configuration

The core is a codec, so there's almost nothing to configure — the "wiring" is
your own broker client plus a couple of optional behaviours.

## Envelope options

`EnvelopeCodec.make` takes the queue name (written to `meta.queue`) and an
optional inbound trace id to continue across a hop (pass `null` to mint a fresh
one):

```java
import com.babelqueue.*;
import java.util.Map;

Envelope env = EnvelopeCodec.make(
    "urn:babel:orders:created",
    Map.of("order_id", 1042L),
    "orders",
    null); // or inbound.traceId() to continue a trace
```

## Dead-letter

On failure, wrap the envelope in an additive `dead_letter` block and publish the
copy to your dead-letter queue (e.g. `orders.dlq`):

```java
Envelope dlq = DeadLetters.annotate(env, "failed", "orders", 3, "boom", "java.lang.RuntimeException");
// publish EnvelopeCodec.encode(dlq) to the "orders.dlq" queue
```

`DeadLetters.annotate` returns a copy — the original envelope is preserved
unchanged inside the dead-lettered message, so any-language consumer can still
read it.

## Unknown-URN strategy

For adapters routing inbound messages, `UnknownUrnStrategy` (`FAIL`, `DELETE`,
`RELEASE`, `DEAD_LETTER`) describes what to do with a URN you don't handle.

Next: [Producing messages](/docs/babelqueue-java/1.x/producing-messages/).