Upgrade spring-petclinic-server to Java 21 and Spring Boot 3.5.3

[Copilot]

Upgrades spring-petclinic-server from Java 8 / Spring Boot 2.1.3 to Java 21 / Spring Boot 3.5.3.

Parent POM

• Spring Boot parent 2.1.3.RELEASE → 3.5.3
• Added java.version=21 property

Dependencies

• Added spring-boot-starter-validation (Jakarta Validation API now separate)
• mysql:mysql-connector-java → com.mysql:mysql-connector-j
• Added jakarta classifier to ehcache
• Added jakarta.xml.bind-api and jaxb-runtime for JAXB support

Namespace Migration (javax → jakarta)

• javax.persistence.* → jakarta.persistence.*
• javax.validation.* → jakarta.validation.*
• javax.xml.bind.* → jakarta.xml.bind.*

Plugin Updates

• pl.project13.maven:git-commit-id-plugin → io.github.git-commit-id:git-commit-id-maven-plugin
• Removed deprecated fork option from spring-boot-maven-plugin
• Fixed build-info to use java.version instead of maven.compiler.source/target

Test Migration (JUnit 4 → JUnit 5)

• org.junit.Test → org.junit.jupiter.api.Test
• Removed @RunWith(SpringRunner.class) annotations
• Updated content-type assertion (Spring Boot 3.x no longer includes charset=UTF-8 in JSON responses)

// Before
import javax.persistence.Entity;
import org.junit.Test;

// After
import jakarta.persistence.Entity;
import org.junit.jupiter.api.Test;

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• http://registry.npmjs.org:80/npm/-/npm-6.14.12.tgz
  • Triggering command: /usr/lib/jvm/temurin-8-jdk-amd64/bin/java /usr/lib/jvm/temurin-8-jdk-amd64/bin/java -classpath /usr/share/apache-maven-3.9.12/boot/plexus-classworlds-2.9.0.jar -Dclassworlds.conf=/usr/share/apache-maven-3.9.12/bin/m2.conf -Dmaven.home=/usr/share/apache-maven-3.9.12 -Dlibrary.jansi.path=/usr/share/apache-maven-3.9.12/lib/jansi-native -Dmaven.multiModuleProjectDirectory=/home/REDACTED/work/spring-petclinic-angularjs/spring-petclinic-angularjs org.codehaus.plexus.classworlds.launcher.Launcher install -DskipTests -U -pl spring-petclinic-client (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Upgrade spring-petclinic-server into Java 21 and Spring Boot 3.5.x

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