Agent skill · software engineering · github
java-helidon
Get best practices for developing applications with Helidon 4 (SE and MP). Use when working with Helidon SE or Helidon MP, HttpService routing, Helidon DB Client, MicroProfile Config, Helidon Security, or Helidon testing in Java 21+ projects.
Why this skill is useful
Provides specific best practices and API changes for Helidon 4 that the AI wouldn't reliably generate on its own.
What it needs
About 8k tokens when loaded. Last updated 2026-08-07. 37,534 stars on the source repository.
What this skill does
Helidon Best Practices Your goal is to help me write high-quality Helidon applications by following established best practices. Helidon 3 → 4 API changes Helidon 4 renamed or resignatured APIs that appear widely in their Helidon 3 form. The left column does not compile on Helidon 4. Check generated code against this table before returning it. Do not use (Helidon 3) Use (Helidon 4) ---------------------------------------------------------- ------------------------------------------------------------------ io.helidon.common.http.Http.Status io.helidon.http.Status io.helidon.webserver.Service io.helidon.webserver.http.HttpService Routing.Rules, update(Routing.Rules) HttpRules, routing(HttpRules) request.path().param("id") request.path().pathParameters().get("id") String s = column.as(String.class) column.getString() or column.get(String.class) dbClient.execute(exec -> ...) returning Single/Multi dbClient.execute() returning Optional<DbRow> / Stream<DbRow> javax. jakarta. helidon-microprofile-tests-junit5 helidon-microprofile-testing-junit5 Value.as(Class) in Helidon 4 returns OptionalValue<T>, not T. This is the single most common Helidon 4 compile error in generated code. Project Setup & Structure Programming Model: Determine whether the project uses Helidon SE or Helidon MP before generating code. Do not mix the two programming models unless explicitly required. Java Version: Use Java 21 or later for Helidon 4 applications. Build Tool: Use Maven (pom.xml) or Gradle (build.gradle) for dependency management. Dependency Management: Use the Helidon BOM or platform to keep Helidon module versions aligned. Package Structure: Organize code by feature or domain, such as com.example.app.order and com.example.app.customer, rather than only by technical layer. Helidon SE Explicit Composition: Construct services and dependencies explicitly in the application bootstrap layer. …
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@skills github/java-helidon