This is an automated email from the ASF dual-hosted git repository. davsclaus pushed a commit to branch chore/camel421-whatsnew-blog in repository https://gitbox.apache.org/repos/asf/camel-website.git
commit 7a15a598c0d0a0ba79cfec160ceef0c7da708216 Author: Claus Ibsen <[email protected]> AuthorDate: Mon Jun 29 09:54:54 2026 +0200 chore: add blog post for Camel 4.21 What's New Co-Authored-By: Claude Opus 4.6 <[email protected]> --- content/blog/2026/07/camel421-whatsnew/index.md | 396 ++++++++++++++++++++++++ 1 file changed, 396 insertions(+) diff --git a/content/blog/2026/07/camel421-whatsnew/index.md b/content/blog/2026/07/camel421-whatsnew/index.md new file mode 100644 index 00000000..bd3ec99d --- /dev/null +++ b/content/blog/2026/07/camel421-whatsnew/index.md @@ -0,0 +1,396 @@ +--- +title: "Apache Camel 4.21 What's New" +date: 2026-07-03 +draft: false +authors: [ davsclaus ] +categories: [ "Releases" ] +keywords: ["apache camel", "whats new", "camel 4", "release", "camel 4.21", "integration framework"] +preview: "Details of what we have done in the Camel 4.21 release." +--- + +Apache Camel 4.21 has just been [released](/blog/2026/07/RELEASE-4.21.0/). + +This release introduces a large set of new features and noticeable improvements that we will cover in this blog post. + +## Camel Core + +### Error Registry + +The Error Registry has been enhanced to capture rich exchange data snapshots at error time, +following the same pattern as BacklogTracer. This includes the message body, headers, exchange properties, +and variables — giving you a complete picture of what was happening when the error occurred. + +Error registry configuration has moved to a dedicated `camel.errorRegistry.*` prefix: + +```properties +camel.errorRegistry.enabled=true +camel.errorRegistry.maximumEntries=100 +camel.errorRegistry.timeToLiveSeconds=300 +``` + +The error registry integrates with the route diagram rendering, allowing you to visualize the +exact path a failed exchange took through your routes. + +### Route Topology + +A new route topology service computes inter-route relationships — which routes send messages to +which other routes (via `direct`, `seda`, `kafka`, etc.). The topology is available through a dev console +and powers the new topology diagram rendering in both the CLI and the embeddable web component. + +See the dedicated [Route Topology](/blog/2026/06/camel-route-topology/) blog post for more details. + +### Group-Scoped Variables + +Variables can now be scoped to a route group. When multiple routes share a `routeGroup`, +they can share variables within that group scope using `variable.group:myVar`: + +```java +from("direct:a").routeGroup("myGroup") + .setVariable("group:counter", simple("${variable.group:counter}++")) + .to("direct:b"); + +from("direct:b").routeGroup("myGroup") + .log("Counter is ${variable.group:counter}"); +``` + +### Exchange Memory Optimization + +We made significant work to reduce memory pressure on the Exchange object: + +- **Copy-on-write headers**: Message headers are now shared across exchange copies (multicast, splitter, etc.) + and only copied when actually modified, reducing allocation overhead. +- **Lazy initialization**: Several internal data structures on the Exchange are now initialized lazily, + reducing the baseline memory footprint. +- **O(1) CaseInsensitiveMap**: The default `CaseInsensitiveMap` used for message headers now uses a custom + hash table with zero-allocation lookups and header key deduplication, making the external + `camel-headersmap` dependency unnecessary (now deprecated). + +### Virtual Threads + +When virtual threads are enabled, the `threads()` EIP now honors `maxQueueSize` +for backpressure. Previously, `maxQueueSize` was silently ignored and tasks were accepted unboundedly. + +A new `Block` rejected policy has been added to `ThreadPoolRejectedPolicy`, where the caller blocks +until capacity becomes available. + +### JSpecify Null Annotations + +The `camel-api` module now uses `@NullMarked` and `@Nullable` annotations from JSpecify to document +nullability contracts across the Camel API surface. This enables compile-time null checking with tools like NullAway. + +### Simple Language + +Several improvements to the Simple language: + +- `floor`/`ceil` now return `long` instead of `int` to avoid overflow for large values. +- `range(N)` in csimple now starts at 1 (consistent with the `simple` language). +- The internal implementation has been refactored into domain-aligned builder classes for better maintainability. + +## Camel CLI + +Camel JBang has been rebranded as **Camel CLI** in the documentation. + +### Camel TUI + +The Camel TUI (Terminal User Interface) is a new feature in heavy development, and we will publish +dedicated blog posts to highlight this feature in more detail. More improvements are coming in the +following releases. + +In this release the TUI received many improvements: + +- **History tab** — Browse the exchange processing history. +- **Error tab** — View errors captured by the error registry with full exchange snapshots. +- **Shell tab** — An embedded shell for advanced CLI usage directly within the TUI. +- **OpenTelemetry tab** — View distributed traces and spans directly in the TUI. +- **Route diagrams** — Graphical route diagram rendering with live metrics overlay in the TUI. +- **Send Message dialog** — Send test messages to routes directly from the TUI. +- **Screenshot action (Shift+F5)** — Capture the current TUI screen as ASCII art. +- **F2 actions menu** — Quick actions including _Run an example_ and _Run Infra Service_. +- **Notifications** — TUI now shows `(n)` notification counts. + +### Embedded MCP Server + +The TUI now includes an embedded MCP server that allows AI coding agents to observe and interact +with a running Camel application's screen. New MCP runtime tools provide access to topology, errors, +thread dumps, exchange history, and the ability to stop routes or send messages. + +### `camel dev` Alias + +A new `camel dev` command has been added as a convenient alias for `camel run --dev`. + +### Auto-Detect application.properties + +The `camel run` and `camel export` commands now auto-detect `application.properties` (and profile-specific +variants) in the current directory and include them automatically. You no longer need to list the +properties file explicitly on the command line. + +### Container-Optimized Docker Export + +The `camel export` command now generates Dockerfiles optimized for container image layer caching. +Dependencies (stable) and application code (volatile) are placed in separate Docker layers, +so rebuilds only update the thin application layer. + +- **Camel Main**: uses `maven-jar-plugin` with classpath manifest and `maven-dependency-plugin:copy-dependencies`. +- **Spring Boot**: uses Spring Boot's `jarmode=tools extract --layers` for 4-layer Docker images. + +### Lazy Plugin Loading + +Plugins are now loaded lazily. Built-in commands that do not consume plugins +(such as `camel get`, `camel version`, `camel ps`) skip plugin discovery entirely, +making these commands faster. Plugin classpath resolution is also cached. + +### Wrapper Renamed + +The `camel wrapper` command now installs scripts as `camel` instead of `camelw`. + +### Quarkus Version Auto-Resolution + +The default Quarkus Platform version is now determined at runtime by querying the Quarkus Extension Registry, +finding the newest platform compatible with the current Camel version. No more stale hardcoded defaults. + +### AI-Friendly Exports + +Exported projects now include an `AGENTS.md` file and a _For AI coding assistants_ section in the generated +`readme.md`, linking to the Apache Camel LLM index for better AI coding assistant context. + +## Route Diagrams + +The new `camel-diagram` component provides route diagram rendering in multiple formats: + +- **ASCII art** — Text-based diagrams for CLI and logging with configurable themes. +- **HTML** — Interactive diagrams with an embeddable `<camel-route-diagram>` web component that renders + routes as SVG with optional live metrics overlay and periodic refresh. +- **Topology** — Inter-route relationship diagrams showing how routes connect to each other. + +The component includes a dev console, integrates with the TUI, and can highlight error paths +from the error registry message history. + +```properties +# show route diagrams with live counters +camel.diagram.enabled=true +``` + +## Camel AI + +### Agent-to-Agent Protocol (A2A) + +A new `camel-a2a` component (Preview) provides support for the +[Agent-to-Agent (A2A) protocol](https://google.github.io/A2A/). As a consumer, it exposes Camel routes +as A2A-compliant agents; as a producer, it calls remote A2A agents. The component also provides an +`a2aSubTask` route step for scoped progress updates. + +### Audio Transcription + +The `camel-openai` component now supports audio transcription (speech-to-text) via the Whisper API. + +The component also now accepts `WrappedFile`, `byte[]`, and `InputStream` bodies for vision models, +so you can pipe files directly from `camel-file`, `camel-ftp`, or `camel-aws2-s3` to an AI model +without conversion issues. + +### LangChain4j Structured Output + +The `camel-langchain4j-agent` component now supports structured outputs, allowing you to specify a +Java class as the response format. The LLM response is automatically parsed into the specified type. + +### MCP Server Improvements + +The Camel MCP Server received further improvements: + +- **Runtime tools** — New tools for route topology, errors, thread dumps, exchange history, + stopping routes, and sending messages to running Camel applications. +- **MCP SDK 2.0** — Embraced the new MCP Java SDK 2.0 API. +- **Claude Code plugin** — The Camel MCP Server is now published as a Claude Code plugin. +- **Route diagram tool** — Generate visual route diagrams via MCP, including ASCII diagrams. +- **Leaner responses** — Reduced token consumption by removing verbose descriptions from catalog + list responses and stripping null fields from JSON responses. + +### Tool Argument Filtering + +Tool argument headers in `camel-langchain4j-tools`, `camel-langchain4j-agent`, and `camel-spring-ai-tools` +are now filtered against the tool's declared parameter schema. Only declared parameters are set as headers, +preventing undeclared LLM-generated arguments from leaking into the Exchange. + +### Multi-Tool Isolation + +When the LLM requests multiple tool invocations within a single request, each tool is now invoked on its +own independent copy of the exchange, guaranteeing complete isolation between tool calls. + +## Observability + +### OpenTelemetry Java Agent in TUI + +A new `--open-telemetry-agent` flag for `camel run`/`camel dev` attaches the OpenTelemetry Java Agent +to the Camel process. An embedded OTLP receiver feeds spans directly into the TUI Spans tab — no +external collector needed. + +```bash +camel dev myRoute.yaml --open-telemetry-agent +``` + +### Reduced Span Verbosity + +Processors that send to an endpoint (`to`, `toD`, `wireTap`, `enrich`) no longer emit a redundant +processor span wrapping the endpoint event span. This reduces span tree depth and total span count. + +### AWS Span Decorators + +New span decorators have been added for AWS components, providing better trace context for AWS service calls. + +### Baggage Management + +The `camel-micrometer-observability` component now supports baggage management for propagating +contextual data across service boundaries. + +## Security Hardening + +This release includes a comprehensive security hardening effort: + +### Header Naming Convention + +Exchange header constants across 30+ components have been aligned to the `Camel*` naming convention +(e.g., `kafka.TOPIC` -> `CamelKafkaTopic`). This ensures that framework-internal headers are properly +filtered by the default `HeaderFilterStrategy` at transport boundaries, preventing header injection attacks. + +Components affected include: Kafka, Salesforce, CXF, Elasticsearch, OpenSearch, JGroups, Jira, IRC, +OpenStack, Web3j, PDF, Solr, and many more. See the [upgrade guide](/manual/camel-4x-upgrade-guide-4_21.html) +for the complete list. + +### Deserialization Hardening + +- Default `ObjectInputFilter` now includes JEP-290 graph-shape limits (`maxdepth=20`, `maxrefs=10000`, + `maxbytes=10485760`) and denies `java.net.**` classes across all deserialization sites. +- JMS `ObjectMessage` support is disabled by default in `camel-jms` and `camel-sjms`. +- Java serialization type converters for `ObjectInput`/`ObjectOutput` have been removed from camel-core. +- Jackson data formats (`camel-jackson`, `camel-jacksonxml`, `camel-jackson-avro`, `camel-jackson-protobuf`) + now block unsafe polymorphic base types by default. + +### Mail Security + +The `camel-mail` component now defaults `useHeaderRecipients`, `useHeaderFrom`, `useHeaderSubject`, +and `useHeaderReplyTo` to `false`, preventing untrusted exchange headers from overriding endpoint-configured +mail settings. + +### CXF WS-Security Optional + +The `cxf-rt-ws-security` dependency in `camel-cxf-soap` is now optional. Most users don't need +WS-Security, and the transitive OpenSAML dependencies hosted on the unreliable `build.shibboleth.net` +repository caused build failures. + +## Canonical YAML DSL + +A new canonical JSON Schema variant (`camelYamlDsl-canonical.json`) removes all implicit patterns (string +shorthands, inline expressions, `oneOf`/`anyOf`/`not` constructs) to provide a simpler, more predictable +schema for tooling and AI assistants. + +A new `camel validate normalize` command rewrites YAML routes from the compact (shorthand) form +to the canonical (explicit) form. Camel also now logs a WARN when YAML routes use compact notation, +encouraging adoption of the canonical style. + +The YAML DSL now supports a classpath-discovered extension point for component-provided custom route step +deserializers, enabling optional modules to contribute YAML step names automatically. + +## Camel Kafka / Spring Boot + +### Spring Kafka Properties Bridge + +When using `camel-kafka-starter` with Spring Boot, the standard `spring.kafka.*` properties are now +automatically bridged to the Camel Kafka component. You no longer need to duplicate settings under both +`spring.kafka.*` and `camel.component.kafka.*`. + +```properties +# These Spring Boot properties are now automatically picked up by Camel Kafka +spring.kafka.bootstrap-servers=localhost:9092 +spring.kafka.consumer.group-id=my-group +spring.kafka.security.protocol=SASL_SSL +``` + +Explicit `camel.component.kafka.*` settings always take precedence. + +### Spring Boot 4.1 + +Upgraded to Spring Boot 4.1. + +## Azure Blob Storage + +The `camel-azure-storage-blob` component gained several new operations: + +- **Index tags** — Set, get, and find blobs by index tags. +- **Blob versions** — List all versions of blobs in a container with version ID and current-version flag. +- **Immutability policies** — Set immutability policies and legal holds on blobs. +- **Soft-delete recovery** — Undelete soft-deleted blobs. +- **Access tier** — Change the access tier of existing blobs. + +## Miscellaneous + +The `camel-bindy` component can now handle parse failures gracefully with a new `continueParseOnFailure` +option, substituting default values instead of aborting the entire unmarshal. + +The `camel-keycloak` component gained support for Keycloak 26+ Organizations API and token revocation +and session logout operations. + +The `camel-nats` component now works properly in JetStream pull mode (previously pull requests were +never issued) and supports manual acknowledgement. + +The `camel-mongodb` consumer now exposes the resume token for change streams. + +The `camel-milo` (OPC UA) component now supports explicit username and password parameters for +handling special characters, and exposes the underlying Eclipse Milo `OpcUaClient` for custom +DataType handling. + +Upgraded many third-party dependencies including Kafka 4.2 client, Kubernetes 7.6 client, +Apache Artemis 2.5, HttpClient 5.6, Testcontainers 2.0.4, and Infinispan 16.2. + +Added Java DSL model writer for full-circle DSL transformation — you can now transform routes +between XML/YAML and Java DSL in both directions. + +## New Components + +- `camel-a2a` - Agent-to-Agent (A2A) protocol integration for AI agents (Preview). +- `camel-shell` - Execute shell commands from Camel routes. + +## Removed Components + +The following previously deprecated components have been removed: + +- `camel-stomp` (unmaintained library since 10+ years) +- `camel-aws-xray` (AWS X-Ray is in maintenance mode since February 2026) +- `camel-guava-eventbus` (deprecated since 4.6) +- `camel-grape` (deprecated since 4.1) +- `camel-elytron` (deprecated since 4.0) +- `camel-github` (replaced by `camel-github2`) + +## Deprecated Components + +The following components are now deprecated: + +- `camel-headersmap` (core now provides equivalent performance) +- `camel-ironmq` (unmaintained since 2017) +- `camel-digitalocean` (unmaintained Java library) +- `camel-irc` (no stable library release since 2007) +- `camel-iec-60870` (NeoScada unmaintained since 2021) +- `camel-paho` (no new release since 2020) +- `camel-reactive-executor-vertx` (experimental, no user feedback) +- `camel-threadpoolfactory-vertx` (experimental, no user feedback) + +## Upgrading + +Make sure to read the [upgrade guide](/manual/camel-4x-upgrade-guide-4_21.html) if you are upgrading from a previous +Camel version. This release has a large upgrade guide due to the header naming convention alignment across 30+ +components and the security hardening changes. + +If you are upgrading from, for example, 4.4 to 4.8, then make sure to follow the upgrade guides for each release +in-between, i.e. +4.4 -> 4.5, 4.5 -> 4.6, and so forth. + +The Camel Upgrade Recipes tool can also be used to automate upgrading. +See more at: https://github.com/apache/camel-upgrade-recipes + +## Release Notes + +You can find additional information about this release in the list of resolved JIRA tickets: + +- [Release notes 4.21](/releases/release-4.21.0/) + +## Roadmap + +The next 4.22 LTS release is planned in August.
