Java 21 and Spring Boot 3.4 upgrade

[yortch]

Upgrade Java Project

🖥️ Project Information

• Project path: c:\Users\jbalderas\source\repos\spring-petclinic-angularjs\spring-petclinic-server
• Java version: 21
• Build tool type: Maven
• Build tool path: C:\Users\jbalderas\apps\apache-maven-3.9.6\bin

🎯 Goals

• Upgrade Java to 21
• Upgrade Spring Boot to 3.4.x

🔀 Changes

Test Changes

	Total	Passed	Failed	Skipped	Errors
Before	3	3	0	0	0
After	3	3	0	0	0

Dependency Changes

Upgraded Dependencies

Dependency	Original Version	Current Version	Module
org.springframework.boot:spring-boot-starter-web	2.1.3.RELEASE	3.4.1	spring-petclinic-server
org.springframework.boot:spring-boot-starter-thymeleaf	2.1.3.RELEASE	3.4.1	spring-petclinic-server
org.springframework.boot:spring-boot-starter-data-jpa	2.1.3.RELEASE	3.4.1	spring-petclinic-server
org.springframework.boot:spring-boot-starter-cache	2.1.3.RELEASE	3.4.1	spring-petclinic-server
org.springframework.boot:spring-boot-starter-actuator	2.1.3.RELEASE	3.4.1	spring-petclinic-server
org.springframework.boot:spring-boot-devtools	2.1.3.RELEASE	3.4.1	spring-petclinic-server
org.springframework.boot:spring-boot-configuration-processor	2.1.3.RELEASE	3.4.1	spring-petclinic-server
org.hsqldb:hsqldb	2.4.1	2.7.3	spring-petclinic-server
org.springframework.boot:spring-boot-starter-test	2.1.3.RELEASE	3.4.1	spring-petclinic-server
javax.cache:cache-api	1.1.0	1.1.1	spring-petclinic-server
org.ehcache:ehcache	3.6.3	3.10.8	spring-petclinic-server
Java	8	21	Root Module

Added Dependencies

Dependency	Version	Module
jakarta.xml.bind:jakarta.xml.bind-api	4.0.2	spring-petclinic-server
org.springframework.boot:spring-boot-starter-validation	3.4.1	spring-petclinic-server
org.junit.jupiter:junit-jupiter	5.11.4	spring-petclinic-server
com.mysql:mysql-connector-j	9.1.0	spring-petclinic-server
org.glassfish.jaxb:jaxb-runtime	4.0.5	spring-petclinic-server

Removed Dependencies

Dependency	Version	Module
mysql:mysql-connector-java	8.0.15	spring-petclinic-server

Code commits

25 files changed, 105 insertions(+), 101 deletions(-)

• 6040910 -- Upgrade Spring Boot from 2.1.3 to 3.3.8 and Java from 8 to 21

• 90b5da1 -- Add explicit version for jakarta.cache:cache-api dependency

• 70d558b -- Use correct jakarta.cache:cache-api version 1.1.2

• 28658b1 -- Revert cache API back to javax.cache as jakarta.cache doesn't exist

• 17ea34e -- Upgrade Spring Boot from 3.3.8 to 3.4.1 and migrate deprecated test annotations

Potential Issues

Behavior Changes

• AbstractClinicServiceTests.java
  • [Severity: MINOR] [Confidence: LOW] The method call changed from get(0) to getFirst(). While both should return the first element, getFirst() is a Java 21 method that may have different exception behavior - it throws NoSuchElementException on empty lists while get(0) throws IndexOutOfBoundsException. This could affect test behavior if the list is unexpectedly empty.
  • [Severity: MINOR] [Confidence: LOW] Changed from get(0) to getFirst() method. The getFirst() method is a new Java 21 feature that provides more semantic clarity but functionally equivalent behavior for accessing the first element.
• PetResourceTests.java
  • [Severity: MINOR] [Confidence: LOW] The expected content type changed from including charset specification to just the media type. This could cause test failures if the actual response includes charset information, as the assertion would no longer match.
  • [Severity: MINOR] [Confidence: LOW] Changed from string literal to MediaType constant. Both represent the same content type, but the constant approach is more maintainable and less error-prone.
• CacheConfig.java
  • [Severity: MINOR] [Confidence: LOW] The method visibility has been reduced from public to package-private. This could break external code that was accessing this method from outside the package, potentially causing compilation errors or runtime failures in dependent modules.
• ClinicServiceImpl.java
  • [Severity: MINOR] [Confidence: LOW] Removal of @Autowired annotation from constructor. In Spring Boot 3.x with single constructor, this annotation is optional and the behavior remains functionally equivalent - Spring will still perform dependency injection.
• OwnerResource.java
  • [Severity: MINOR] [Confidence: LOW] Removal of @Autowired annotation from constructor. In Spring Boot 3.x with single constructor, this annotation is optional and the behavior remains functionally equivalent - Spring will still perform dependency injection.
  • [Severity: MINOR] [Confidence: LOW] Replaced verbose @RequestMapping with more specific @PostMapping. This is functionally equivalent - both map POST requests to the same endpoint with identical behavior.
  • [Severity: MINOR] [Confidence: LOW] Replaced verbose @RequestMapping with @GetMapping and removed explicit parameter name from @PathVariable. Both changes are functionally equivalent - the mapping behavior and parameter binding remain identical.
  • [Severity: MINOR] [Confidence: LOW] Replaced verbose @RequestMapping with @PutMapping and removed explicit parameter name from @PathVariable. Both changes are functionally equivalent - the mapping behavior and parameter binding remain identical.
• PetResource.java
  • [Severity: MINOR] [Confidence: LOW] Removal of @Autowired annotation from constructor. In Spring Boot 3.x with single constructor, this annotation is optional and the behavior remains functionally equivalent - Spring will still perform dependency injection.
  • [Severity: MINOR] [Confidence: LOW] Removed explicit parameter name from @PathVariable. This is functionally equivalent - Spring will automatically match the parameter name with the path variable name.
  • [Severity: MINOR] [Confidence: LOW] Removed explicit parameter name from @PathVariable. This is functionally equivalent - Spring will automatically match the parameter name with the path variable name.
• VetResource.java
  • [Severity: MINOR] [Confidence: LOW] Removal of @Autowired annotation from constructor. In Spring Boot 3.x with single constructor, this annotation is optional and the behavior remains functionally equivalent - Spring will still perform dependency injection.
• VisitResource.java
  • [Severity: MINOR] [Confidence: LOW] Removal of @Autowired annotation from constructor. In Spring Boot 3.x with single constructor, this annotation is optional and the behavior remains functionally equivalent - Spring will still perform dependency injection.
  • [Severity: MINOR] [Confidence: LOW] Removed explicit parameter name from @PathVariable. This is functionally equivalent - Spring will automatically match the parameter name with the path variable name.
  • [Severity: MINOR] [Confidence: LOW] Removed explicit parameter name from @PathVariable. This is functionally equivalent - Spring will automatically match the parameter name with the path variable name.

[arey]

Thanks @yortch for this major upgrade.
Did you test the application? Is everything ok?

[arey]

suggestion: declare version in the <properties> section