Migrate from Java 6 to Java 11 with Dropwizard 2.1.12

[devin-ai-integration]

Summary

Migrates the project from Java 6 / Dropwizard 1.0.5 to Java 11 / Dropwizard 2.1.12. This is a major framework upgrade touching build configuration, dependency management, source compatibility, and test infrastructure.

Build & Dependencies (pom.xml)

• Decoupled Dropwizard BOM version from ${project.version} into a <dropwizard.version> property set to 2.1.12
• Added dropwizard-dependencies BOM import alongside the existing dropwizard-bom
• Added explicit JAXB/Jakarta dependencies (jakarta.xml.bind-api, jaxb-runtime, jakarta.activation-api) with versions pinned in <dependencyManagement> to satisfy dependency convergence
• Updated compiler plugin from source/target 1.6 to release 11
• Updated all Maven plugin versions (surefire 2.19.1→3.1.2, shade 2.4.3→3.5.1, compiler 3.6.0→3.11.0, etc.)
• Added module-info.class exclusion in shade plugin filter

Source Changes

• EmployeeConfiguration.java: @NotEmpty import moved from deprecated org.hibernate.validator.constraints to javax.validation.constraints
• EmployeeDAO.java: Added explicit cast of namedQuery() result to Query<Employee> for Dropwizard 2.x Hibernate API compatibility
• AppTest.java: Migrated from JUnit 3 (junit.framework) to JUnit 5 (org.junit.jupiter)

Config & Docs

• Updated ALPN comment in example.yml (Java 11 has native ALPN support)
• Updated README.md to reference Dropwizard 2.1.12 and Java 11

mvn clean install passes on JDK 11.

Review & Testing Checklist for Human

• Verify the DAO unchecked cast is safe at runtime: EmployeeDAO.findAll() casts namedQuery() result from Query<?> to Query<Employee>. This compiles and passes the trivial test suite, but should be verified with actual database operations (POST an employee, then GET the list).
• H2 database compatibility: Dropwizard 2.1.12's BOM pulls H2 2.2.x (up from ~1.4.x). H2 2.x has breaking changes in SQL mode and URL handling. Run java -jar target/DropwizardEmployee-1.0.5.jar db migrate example.yml then start the server and exercise the CRUD endpoints.
• JAXB version convergence: jaxb-runtime is pinned to 2.3.3 in dependencyManagement, overriding Hibernate 5.6.15's transitive 2.3.1. Verify no runtime ClassNotFoundException or NoSuchMethodError from Hibernate's XML binding paths.
• Smoke test the running application: mvn package && java -jar target/DropwizardEmployee-1.0.5.jar server example.yml — verify the app boots on port 8080, POST/GET /employee work, and admin on 8081 responds.

Notes

• The existing test suite is trivial (assertTrue(true)) and provides no meaningful coverage of the migration. Manual smoke testing is essential.
• The project version remains 1.0.5 (only the Dropwizard framework version was upgraded). The jar filename in the README still references DropwizardEmployee-1.0.5.jar which is correct.

Link to Devin session: https://app.devin.ai/sessions/557bb933cbe84da99855f70a1ff44c29
Requested by: @WesternConcrete

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✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

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