Upgrade Java version from 17 to 21 LTS

[devin-ai-integration]

Description

Upgrades the project from Java 17 to Java 21 LTS. This includes updating the build configuration and CI/CD pipeline to use the latest LTS version of Java.

Changes

• Updated java.sourceCompatibility to JavaVersion.VERSION_21
• Updated Kotlin jvmTarget to "21"
• Updated Detekt jvmTarget from "14" to "21" (was outdated)
• Updated GitHub Actions workflow to use JDK 21 with Temurin distribution
• Updated JaCoCo from 0.8.7 to 0.8.12 (required for Java 21 support)

Compatibility Verification

The following dependencies are compatible with Java 21:

• Kotlin 1.9.20
• Spring Boot 3.2.3
• Gradle 8.6
• JaCoCo 0.8.12 (0.8.11+ officially supports Java 21)

Build and tests were verified locally with Java 21.

Updates since last revision

• Added JaCoCo upgrade from 0.8.7 to 0.8.12. JaCoCo 0.8.7 does not support Java 21 class files (version 65), which caused CI to fail with Unsupported class file major version 65 error.

Type of change

• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have added examples for the new scenarios in the relevant modules

Human Review Checklist

• Verify CI passes with Java 21
• Confirm all tests pass with the new Java version
• Note: Detekt jvmTarget was updated from 14 to 21 (was already outdated for Java 17)
• Note: JaCoCo upgrade to 0.8.12 is required for Java 21 class file support

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Link to Devin run: https://lowes.devinenterprise.com/sessions/61c40f7742954262a1934cc9f1d8248c
Requested by: harsha.shivakumar@lowes.com (@harshaskumar05)

[devin-ai-integration]

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