Migrate to Java 17 + Spring Boot 3.2.5

[devin-ai-integration]

Summary

Migrates the project from Java 8 / Spring Boot 2.0.2.RELEASE to Java 17 / Spring Boot 3.2.5, modernizes the build tooling, and fixes two Spring Boot 3.x compatibility issues in Application.java.

File-by-file changes

• pom.xml
  • <java.version>: 1.8 → 17
  • Spring Boot parent: 2.0.2.RELEASE → 3.2.5
  • Removed spring-boot-properties-migrator (only needed for 1.x→2.x; obsolete in 3.x)
• build.gradle
  • sourceCompatibility / targetCompatibility: 1.8 → 17
  • Spring Boot Gradle plugin: 2.0.2.RELEASE → 3.2.5
  • compile(...) → implementation(...) and testCompile(...) → testImplementation(...) (removed in modern Gradle)
  • bootJar { baseName = ... } → archiveBaseName = ... (Gradle 8 compatibility)
  • Added spring-boot-starter-jdbc and runtime com.h2database:h2 so the Gradle build matches the Maven dependency set and Application.java (which uses JdbcTemplate) actually compiles
• gs-spring-boot.iml: LANGUAGE_LEVEL="JDK_1_8" → JDK_17
• .mvn/wrapper/maven-wrapper.properties: Apache Maven 3.3.9 → 3.9.6
• gradle/wrapper/gradle-wrapper.properties: Gradle 4.6 → 8.7
• src/main/java/hello/Application.java
  • DROP TABLE customers IF EXISTS → DROP TABLE IF EXISTS customers (standard SQL required by newer H2)
  • Replaced deprecated jdbcTemplate.query(sql, Object[] args, RowMapper) overload with the varargs overload jdbcTemplate.query(sql, RowMapper, args...) (still type-safe; no behavior change)

Local verification

• ./mvnw clean package -DskipTests → BUILD SUCCESS (Maven 3.9.6, Java 17). Note: pom.xml has <packaging>pom</packaging>, so the Maven build does not compile sources itself — Gradle is the build that compiles the Java sources.
• ./gradlew clean build --no-daemon → BUILD SUCCESSFUL (Gradle 8.7, Java 17), produces build/libs/gs-spring-boot-0.1.0.jar.

Review & Testing Checklist for Human

• Run ./gradlew clean build locally on Java 17 to confirm the jar builds.
• Run ./gradlew bootRun (or java -jar build/libs/gs-spring-boot-0.1.0.jar) and hit each endpoint to verify behavior is unchanged:
  • GET / (greeting)
  • GET /datetime
  • GET /topic
  • GET /topic/string/operation
  • GET /topic/file/operation
• Confirm the application starts cleanly with no Spring Boot 3 deprecation/migration warnings related to removed properties.

Notes

• The original build.gradle did not declare spring-boot-starter-jdbc / h2, so it could not compile Application.java even before this migration. I added them to keep the two build files (Maven and Gradle) consistent and to fulfill the "Gradle build should compile" requirement.
• pom.xml keeps <packaging>pom</packaging> (unchanged from master), so mvn does not produce a jar. Use Gradle to produce the runnable artifact.
• No javax.* → jakarta.* rewrites were necessary — the source tree does not import any javax.* Spring/Servlet packages.

Link to Devin session: https://app.devin.ai/sessions/0e0a7eebafba43b686ce210e93f85040
Requested by: @sophialyssy-sys

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Test results — all primary endpoint checks passed

Built the migrated project on Java 17, booted the resulting jar, watched startup logs, and hit every endpoint from the original spec.

Heads-up (please read before merging)

The original Application.java had a hard-coded fetch of http://gturnquist-quoters.cfapps.io/api/random inside a @Bean CommandLineRunner. That host no longer resolves, so on Spring Boot 3.x the runner threw UnknownHostException and aborted startup before Tomcat began serving any endpoint. To make the user-requested "verify endpoints work" check possible, I added a try { ... } catch (Exception e) { log.warn("Skipping demo quote fetch: {}", e.getMessage()); } around both call sites in commit 47f4e2b on this branch. This is a pre-existing issue unrelated to the migration itself; flagging it so it's not a surprise during review.

Results

#	Check	Result
1	./gradlew clean build on Java 17 produces build/libs/gs-spring-boot-0.1.0.jar	passed
2	App boots with Spring Boot :: (v3.2.5) banner, Tomcat on :8080, Started Application logged	passed
3	New H2 DDL (DROP TABLE IF EXISTS customers) + new varargs jdbcTemplate.query(sql, mapper, "Josh") both execute at startup and return exactly 2 rows (Josh Bloch, Josh Long)	passed
4	GET / → {"id":1,"content":"Hello, World!"}	passed
5	GET /datetime → 200, body starts with Greetings from Spring Boot! and includes all expected fields	passed
6	GET /topic → 200, 3-element JSON array with spring, java, javascript	passed
7	GET /topic/string/operation → 200, includes Joining All String ID's with JOIN method: spring:java:javascript	passed
8	GET /topic/file/operation → 200, includes temp.txt filter result Hello, this, is, Rehman	passed
9	SIGINT shutdown is clean (HikariPool-1 - Shutdown completed.)	passed

Boot log highlights (click to expand)

 :: Spring Boot ::                (v3.2.5)
2026-05-11T21:25:51.396Z  INFO 8757 --- [main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port 8080 (http) with context path ''
2026-05-11T21:25:51.414Z  INFO 8757 --- [main] hello.Application                        : Started Application in 2.52 seconds (process running for 3.091)
2026-05-11T21:25:51.503Z  WARN 8757 --- [main] hello.Application                        : Skipping demo quote fetch: I/O error on GET request for "http://gturnquist-quoters.cfapps.io/api/random": gturnquist-quoters.cfapps.io
2026-05-11T21:25:51.505Z  INFO 8757 --- [main] hello.Application                        : Creating tables
2026-05-11T21:25:51.710Z  INFO 8757 --- [main] hello.Application                        : Inserting customer record for John Woo
2026-05-11T21:25:51.711Z  INFO 8757 --- [main] hello.Application                        : Inserting customer record for Jeff Dean
2026-05-11T21:25:51.711Z  INFO 8757 --- [main] hello.Application                        : Inserting customer record for Josh Bloch
2026-05-11T21:25:51.711Z  INFO 8757 --- [main] hello.Application                        : Inserting customer record for Josh Long
2026-05-11T21:25:51.734Z  INFO 8757 --- [main] hello.Application                        : Querying for customer records where first_name = 'Josh':
2026-05-11T21:25:51.751Z  INFO 8757 --- [main] hello.Application                        : Customer{id=3, firstName='Josh', lastName='Bloch'}
2026-05-11T21:25:51.751Z  INFO 8757 --- [main] hello.Application                        : Customer{id=4, firstName='Josh', lastName='Long'}

This log alone proves three migration-specific things at once: the Spring Boot 3.2.5 parent/plugin took effect (banner version), the new H2 DROP TABLE IF EXISTS syntax ran without throwing, and the new varargs JdbcTemplate.query overload returned both Josh rows.

Endpoint responses (click to expand)

$ curl -s -i http://localhost:8080/
HTTP/1.1 200
Content-Type: application/json

{"id":1,"content":"Hello, World!"}

$ curl -s -i 'http://localhost:8080/?name=Devin'
HTTP/1.1 200
Content-Type: application/json

{"id":2,"content":"Hello, Devin!"}

$ curl -s -i http://localhost:8080/datetime
HTTP/1.1 200
Content-Type: text/plain;charset=UTF-8

Greetings from Spring Boot! ----------------------Datetime now is 2026-05-11T21:26:20.133048590----------------------Datetime tomorrow will be 2026-05-12T21:26:20.133048590----------------------Datetime of previous month was 2026-04-11T21:26:20.133048590----------------------Is this a leap year ?  false----------------------Default system zone id   Etc/UTC-------------------Time in California: 2026-05-11T21:26:20.133048590-05:00[Canada/Central]

$ curl -s -i http://localhost:8080/topic
HTTP/1.1 200
Content-Type: application/json

[{"id":"spring","subjectName":"Spring Framework","subjectDescription":"Spring Framework Description"},{"id":"java","subjectName":"Core Java","subjectDescription":"Java Description"},{"id":"javascript","subjectName":"javascript Framework","subjectDescription":"javascript Framework Description"}]

$ curl -s -i http://localhost:8080/topic/string/operation
HTTP/1.1 200
Content-Type: text/plain;charset=UTF-8

Joining All String ID's with JOIN method: spring:java:javascript-------------Get all ID characters, select distict and sort with ID=   :acgijnprstv-------------Split All Id With Colon,Select ID With "Java" Keyword, Then Sort Then Join java:javascript-------------Return All ID having character 'g' in it:  [spring]

$ curl -s -i http://localhost:8080/topic/file/operation
HTTP/1.1 200
Content-Type: text/plain;charset=UTF-8

---------Find all files in path and sort:    README.md; application.properties; build; build.gradle; gradle; gradlew; gradlew.bat; gs-spring-boot.iml; mvnw; mvnw.cmd; pom.xml; src; target; temp.txt; test-plan.md----------Find File in present directory which strats with "grad",provided maximum depth=25 and sort : gradle; gradle/wrapper; gradle/wrapper/gradle-wrapper.jar; gradle/wrapper/gradle-wrapper.properties; gradlew; gradlew.bat----------Find File in present directory which strats with "grad",provided maximum depth=25 and sort :  with walk functiongradle; gradle/wrapper; gradle/wrapper/gradle-wrapper.jar; gradle/wrapper/gradle-wrapper.properties; gradlew; gradlew.bat---------Read "temp.txt" file with stream functions, having "print" witin it:   Hello, this, is, Rehman

Tested by: Devin session

[devin-ai-integration]

✅ Devin Review: No Issues Found

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

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