build(java): align toolchain and runtime to Java 25

[cristianrcv]

Summary

Aligns tower-agent with the org-wide Java guideline in seqeralabs/adr#51 (system/2026-07-23-java-version.md), which supersedes the 2024-12-03 Java 17/21 ADR: build on a Java 25 toolchain and target Java 25 bytecode.

Profile classification

The ADR defines two profiles and picks the compile target per module by whether it depends on Micronaut:

• Profile A (default) — Java 25 toolchain, --release 17 target. For modules with no direct or indirect Micronaut dependency (shared libs, API models/clients, anything on the Nextflow classpath).
• Profile B — Java 25 language and bytecode, no --release cap. For modules that explicitly require Micronaut at runtime.

tower-agent is a single-module Micronaut runtime application — it applies io.micronaut.application with runtime("netty") and declares Micronaut implementation dependencies (build.gradle) — so it is Profile B. It is a standalone agent, never loaded by the Nextflow Java 17 runtime.

What changed

• build.gradle: Gradle toolchain JavaLanguageVersion.of(21) -> of(25).
• build.gradle: added sourceCompatibility / targetCompatibility = JavaVersion.VERSION_25.
• build.gradle: removed options.release = 21 from compileJava (no --release cap under Profile B).
• .github/workflows/build.yml: java-version: '21' -> '25' (GraalVM setup + JReleaser setup).
• .github/workflows/build.yml: JReleaser setup-java distribution adopt -> corretto, the ADR's preferred Linux distribution.
• .github/workflows/security_submit_dependencies.yml: java-version: '21' -> '25' (GraalVM setup).
• gradle/wrapper: Gradle 9.3.1 -> 9.6.1, the ADR's mandated minimum.

No Groovy sources in this module, so the ADR's separate Groovy source/target mechanism does not apply.

Why

Micronaut 5 publishes Java-25-only artifacts, so any module with a Micronaut runtime dependency is necessarily Profile B. Adopting the Java 25 toolchain and target now keeps tower-agent on the org-wide baseline and unblocks the eventual Micronaut 5 upgrade (this PR stays on Micronaut 4.6.2).

Runtime impact

The release includes a SINGLE_JAR distribution (tw-agent.jar in jreleaser.yml) that users run on their own JVM. Java 25 bytecode raises that jar's floor to JRE 25+ — previously 21, since master already targeted 21. The native-image binaries are self-contained and unaffected. This is a deliberate, accepted consequence of Profile B and should be called out in the release notes.

How to verify

• CI (build.yml, security_submit_dependencies.yml) runs on Java 25 — all checks green on this branch.
• ./gradlew build compiles with a Java 25 toolchain; emitted bytecode is class-file major version 69 (Java 25).
• graalvm-community and corretto both provide Java 25 in the CI actions.

🤖 Generated with Claude Code

[pditommaso]

Updated this PR to the refined two-profile Java model from seqeralabs/adr#51 (system/2026-07-23-java-version.md), superseding the earlier "Java 25 toolchain / bytecode 17 everywhere" approach.

Classification: tower-agent is a single-module Micronaut runtime application (it applies the Micronaut application plugin with runtime("netty") and declares implementation Micronaut dependencies), so it falls under Profile B — build on the Java 25 toolchain and target Java 25 (no --release 17 cap). Micronaut's Java-25-only artifacts make this the required profile; the agent is a standalone binary and is never loaded by the Nextflow Java-17 runtime.

Change (build.gradle):

• Removed options.release = 17 from compileJava.
• Added sourceCompatibility = JavaVersion.VERSION_25 / targetCompatibility = JavaVersion.VERSION_25 to the java {} block (kept the Java 25 toolchain).

Verify: ./gradlew compileJava passes on a JDK 25 toolchain; emitted bytecode is class-file major version 69 (Java 25), confirming Profile B.

No Groovy sources in this module, so the Groovy source/target mechanism does not apply here.