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CAMEL-23112: Lower minimum JDK requirement from 21 to 17#21991

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gnodet wants to merge 8 commits intomainfrom
camel-jdk17-support
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CAMEL-23112: Lower minimum JDK requirement from 21 to 17#21991
gnodet wants to merge 8 commits intomainfrom
camel-jdk17-support

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@gnodet gnodet commented Mar 13, 2026 •
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Summary

  • Lower the minimum JDK version from 21 to 17 using Multi-Release JAR (MRJAR) infrastructure
  • JDK 21+ users retain all benefits (virtual threads, ScopedValue) — they are loaded automatically via MRJAR at runtime
  • JDK 17 users get platform threads and ThreadLocal as graceful fallbacks

Changes

  • Root pom.xml: jdk.version 21 → 17
  • CamelThreadFactory: JDK 17 base version uses new Thread(). JDK 21 version (with Thread.ofVirtual()/Thread.ofPlatform()) moved to src/main/java21/ MRJAR directory in camel-util
  • JsonObject: Replaced List.getLast() (JDK 21 SequencedCollection) with list.get(list.size() - 1), and String.splitWithDelimiters() (JDK 21) with a Pattern/Matcher equivalent
  • ManagedVirtualThreadExecutorTest: Added @EnabledForJreRange(min = JAVA_21) since it uses Executors.newVirtualThreadPerTaskExecutor()

Trade-offs

Benefits Costs
Broader adoption (JDK 17 LTS widely deployed) Virtual threads unavailable on JDK 17
Lower barrier for enterprise users ScopedValue falls back to ThreadLocal
Aligns with JDK 17 LTS support (until Sept 2029) CI matrix grows (17 + 21 + 25)

Test plan

  • Full build and test on JDK 17
  • Full build and test on JDK 21 (verify MRJAR virtual threads still work)
  • Full build and test on JDK 25 (verify ScopedValue via MRJAR)
  • Verify camel-util JAR contains META-INF/versions/21/org/apache/camel/util/concurrent/CamelThreadFactory.class

JIRA: https://issues.apache.org/jira/browse/CAMEL-23112

@gnodet @claude
Lower minimum JDK requirement from 21 to 17
834705b 
- Change jdk.version from 21 to 17 in root pom.xml
- Create JDK 17 fallback for CamelThreadFactory using new Thread()
- Move JDK 21 CamelThreadFactory (virtual threads) to MRJAR java21/ directory
- Replace List.getLast() (JDK 21) with index-based access in JsonObject
- Replace String.splitWithDelimiters() (JDK 21) with Pattern/Matcher in JsonObject
- Add @EnabledForJreRange(min=JAVA_21) to ManagedVirtualThreadExecutorTest

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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gnodet and others added 7 commits March 13, 2026 15:08
@gnodet @claude
Use reflection for JDK 19/20 SSLParameters methods
727712f 
SSLParameters.getNamedGroups/setNamedGroups (JDK 20) and
getSignatureSchemes/setSignatureSchemes (JDK 19) are called
via reflection so the code compiles and runs on JDK 17.
On JDK 17, these SSL configuration options are silently skipped.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
@gnodet @claude
Fix remaining JDK 21+ API usages in camel-support
4466da6 
- Replace Executors.newThreadPerTaskExecutor() (JDK 21) with
  reflection in DefaultThreadPoolFactory VIRTUAL enum
- Replace Thread.threadId() (JDK 19) with Thread.getId() in
  ExpressionBuilder.threadIdExpression()

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
@gnodet
Merge remote-tracking branch 'origin/main' into camel-jdk17-support
d99ccce
@gnodet @claude
Fix PQC named groups method to use reflection for JDK 17 compat
5af17a2 
The applyPqcNamedGroupDefaults method added in main uses
SSLParameters.getNamedGroups() (JDK 20+) directly. Use the
reflection-based getNamedGroupsFromParams() helper instead.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
@gnodet @claude
Fix SSLContextParametersTest to compile with --release 17
033d793 
Use reflection-based helpers for SSLParameters.getNamedGroups() and
getSignatureSchemes() (JDK 20/19 APIs) and add @EnabledForJreRange
annotations to skip these tests on JDK < 21 at runtime.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
@gnodet @claude
Fix ManagedVirtualThreadExecutorTest to compile with --release 17
237e40c 
Use reflection to call Executors.newVirtualThreadPerTaskExecutor()
which is a JDK 21 API not available with --release 17 compilation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
@gnodet @claude
Fix List.addFirst() usage for JDK 17 compatibility
7975377 
Replace List.addFirst() (JDK 21 SequencedCollection) with
List.add(0, ...) in SpringAiImageOllamaIT.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
@gnodet gnodet changed the title Lower minimum JDK requirement from 21 to 17 CAMEL-23112: Lower minimum JDK requirement from 21 to 17 Mar 13, 2026
@gnodet gnodet marked this pull request as ready for review March 14, 2026 21:36
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@davsclaus davsclaus davsclaus approved these changes

@oscerd oscerd oscerd approved these changes

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@gnodet @davsclaus @oscerd