Upgrade Spring Boot 2.0.2 → 2.7.18 with Java 17 support

[devin-ai-integration]

Summary

Upgrades the project from Spring Boot 2.0.2 (Java 8) to Spring Boot 2.7.18 (Java 17). Spring Boot 2.7.x is the last 2.x line and supports Java 17 without requiring the javax→jakarta migration.

Phase 1 — Build config updates

File	Change
pom.xml	Spring Boot 2.0.2.RELEASE → 2.7.18, Java 1.8 → 17, removed spring-boot-properties-migrator dependency
build.gradle	Plugin version → 2.7.18, sourceCompatibility/targetCompatibility → 17, baseName → archiveBaseName, compile → implementation, testCompile → testImplementation
gradle/wrapper/gradle-wrapper.properties	Gradle 4.6 → 7.6.4 (required for Java 17)
gs-spring-boot.iml	JDK_1_8 → JDK_17

Phase 2 — Application code fixes

File	Change
Application.java	H2 SQL: DROP TABLE customers IF EXISTS → DROP TABLE IF EXISTS customers (H2 2.x standard SQL)
Application.java	JdbcTemplate.query(): migrated from deprecated new Object[]{} parameter style to varargs (RowMapper before bind params)
Application.java	Removed defunct gturnquist-quoters.cfapps.io REST client calls and the CommandLineRunner bean that used them

Phase 3 — Verification

• Maven build (./mvnw clean package) succeeds with JDK 17

Review & Testing Checklist for Human

• Run ./mvnw spring-boot:run with JDK 17 and verify app starts without errors
• Check logs for "Creating tables" and customer query output (H2 init)
• Test endpoints: GET /, GET /datetime, GET /topic, GET /topic/string/operation, GET /topic/file/operation
• Verify the Gradle build also works: ./gradlew clean build (Gradle wrapper updated to 7.6.4)

Notes

• The RestTemplate bean is retained for potential future use, but the defunct CommandLineRunner bean that called gturnquist-quoters.cfapps.io has been removed.
• The Quote and Value model classes remain in the codebase but are no longer called at startup.

Link to Devin session: https://app.devin.ai/sessions/d78092399dc347c5a22a7fa06709ed32
Requested by: @sophialyssy-sys

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