Oracle has released version 4.4.0 of their microservices framework, Helidon, featuring alignment with the OpenJDK release cadence, support via the new Java Verified Portfolio, new core capabilities, and agentic AI support for LangChain4j.
Helidon will change its familiar semantic versioning to match the OpenJDK six-month release cadence. Starting with the release of JDK 27 in September 2026, Helidon 4.4.0 today will change to Helidon 27 and adopt the tip and tail model practiced by OpenJDK.
Helidon will be included in the new Java Verified Portfolio (JVP), a “curated set of Oracle-validated Java tools, frameworks, and libraries.” Introduced at JavaOne 2026, the JVP will also feature commercial support for JavaFX, which has been reestablished by Oracle due to customer demand and the need for advanced visualizations in AI-powered applications.
Helidon Declarative, introduced in Helidon 4.3.0, allows for an inversion-of-control style programming model in Helidon SE. It originally featured three features, namely: HTTP Server Endpoint, Scheduling and Fault Tolerance. Built on top of Helidon Inject, introduced in Helidon 4.2.0, Helidon Declarative adds these new features to complement the original three:
Helidon Declarative is an incubating feature and is, therefore, subject to change.
This release also introduces Helidon JSON, a new JSON processing library optimized for virtual threads and modern Java applications. Helidon JSON consists of two modules; helidon-json-binding for object serialization and deserialization; and helidon-json for fundamental JSON parsing and generation.
The approach used in Helidon JSON includes: generation of Java source code at compile time; use of an annotation processor to generate type-safe converters; execution without reflection at runtime; and code generation that is both readable and debuggable.
Integration with LangChain4j, introduced in Helidon 4.2.0, has been enhanced with support for agents. Developers can take advantage of two common execution patterns: workflows, a set of abstractions to programmatically orchestrate multiple agents and create agentic workflow patterns; and dynamic agents, a ready-to-use supervisor agent that can manage a set of subagents.
The following example, as presented in this blog post, demonstrates how to declaratively create an agent:
@Ai.Agent("helidon-mp-expert")
@Ai.ChatModel("openai-cheap-model")
@Ai.Tools(value = ProjectNameGeneratorTool.class)
@Ai.McpClients(value = {"first-mcp-client", "second-mcp-client"})
public interface HelidonMpExpert {
@UserMessage("""
You are a Helidon MP expert.
Analyze the following user request about Helidon MP and provide
the best possible answer.
Always warn against using native image and stress out that
Helidon MP requires Jakarta APIs.
The user request is {{request}}.
""")
@Agent(value = "A Helidon MP expert", outputKey = "response")
String askExpert(@V("request") String request);
Agents may be defined declaratively, registered as a singleton or configured via Helidon Config.
Originally named J4C (Java for Cloud), Helidon was introduced to the Java community in September 2018. It was designed to be simple and fast, and has two versions: Helidon SE and Helidon MP.
Helidon SE, a functional-style API, originally featured three core components to create a microservice – a web server, configuration, and security – for building microservices-based applications. An application server is not required. With the release of Helidon 2.0 in June 2020, a new web client and database client were added to Helidon SE along with a new command-line tool.
Helidon MP, a declarative-style API, is an implementation of the MicroProfile specifications. Helidon 4.4.0 supports MicroProfile 6.1.
Helidon SE versions 1.0 through 3.0 featured a web server built on top of Netty, the asynchronous, event-driven network application framework. The WebServer interface includes support for configuration, routing, error handling, and building metrics and health endpoints.
In preparation for Helidon 4.0, Helidon introduced an alpha version of a new web server, codenamed Helidon Níma, in September 2022. Níma, a Greek word for thread, was based on JEP 444, Virtual Threads. The new web server was finalized with the release of Helidon 4.0 in October 2023.
More details on this release, including breaking changes and deprecations, may be found in the release notes.
