build(log4j2): Pin compilation to JDK 8 via Maven Toolchains#616
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Release 1.6.3 was built on a JDK that does not run annotation processors by default, which silently dropped the Log4j2 plugin descriptor (META-INF/.../Log4j2Plugins.dat) for LambdaAppender, LambdaTextFormat, and LambdaJsonFormat. The published artifact was broken at runtime: log4j could not resolve <Lambda>, <LambdaTextFormat>, or <LambdaJsonFormat> elements in user log4j2.xml configurations. Configure maven-toolchains-plugin to require a JDK 8 toolchain so javac comes from a JDK that runs annotation processors by default, regardless of which JVM Maven is invoked under. The version range [1.8,9) matches both "1.8" and "8". The existing GitHub Actions workflow at .github/workflows/aws-lambda-java-log4j2.yml uses actions/setup-java@v5 with java-version: 8 and distribution: corretto. setup-java@v5 auto-generates a ~/.m2/toolchains.xml entry with <version>8</version>, which the [1.8,9) range matches, so no workflow changes are required. When no matching JDK 8 toolchain is available, the build now fails fast at the validate phase with a clear "Cannot find matching toolchain definitions" error instead of silently producing an artifact missing its plugin descriptor.
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Thanks for the contribution this would have prevented #612. |
darklight3it
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May 23, 2026
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darklight3it
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LGTM 🚀 this should be merged once the basic tests on #615 are exercised.
M-Elsaeed
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May 23, 2026
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Release 1.6.3 was built on a JDK that does not run annotation processors by default, which silently dropped the Log4j2 plugin descriptor (META-INF/.../Log4j2Plugins.dat) for LambdaAppender, LambdaTextFormat, and LambdaJsonFormat. The published artifact was broken at runtime: log4j could not resolve
<Lambda>,<LambdaTextFormat>, or<LambdaJsonFormat>elements in user log4j2.xml configurations.Configure maven-toolchains-plugin to require a JDK 8 toolchain so javac comes from a JDK that runs annotation processors by default, regardless of which JVM Maven is invoked under. The version range [1.8,9) matches both "1.8" and "8".
The existing GitHub Actions workflow at .github/workflows/aws-lambda-java-log4j2.yml uses actions/setup-java@v5 with java-version: 8 and distribution: corretto. setup-java@v5 auto-generates a ~/.m2/toolchains.xml entry with 8, which the [1.8,9) range matches, so no workflow changes are required.
When no matching JDK 8 toolchain is available, the build now fails fast at the validate phase with a clear "Cannot find matching toolchain definitions" error instead of silently producing an artifact missing its plugin descriptor.
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.