Use java 21 (#158)

Author: pboos

.github/workflows/check.yml

@@ -11,11 +11,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-      - name: Set up JDK 17
+      - name: Set up JDK
         uses: actions/setup-java@v3
         with:
-          java-version: '17'
-          distribution: 'adopt'
+          distribution: temurin
+          java-version: 21
       - name: Validate Gradle wrapper
         uses: gradle/wrapper-validation-action@v1.0.6
       - name: Checkstyle

.github/workflows/publish.yml

@@ -13,11 +13,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-      - name: Set up JDK 17
+      - name: Set up JDK
         uses: actions/setup-java@v3
         with:
-          java-version: '17'
-          distribution: 'adopt'
+          distribution: temurin
+          java-version: 21
       - name: Validate Gradle wrapper
         uses: gradle/wrapper-validation-action@v1.0.6
       - name: Build sourcesJar and javadocJar

.github/workflows/repository-maintenance.yml

@@ -16,7 +16,7 @@ jobs:
         name: Setup Java
         with:
           distribution: temurin
-          java-version: 17
+          java-version: 21
       - name: Generate and submit dependency graph
         uses: gradle/actions/dependency-submission@v4.1.0
         with:

build.gradle

@@ -3,8 +3,6 @@ plugins {
     alias(libs.plugins.nexus.publish)
 }
 
-def javaVersion = providers.environmentVariable("JAVA_BUILD_VERSION").getOrElse("17")
-
 apply from: "${rootDir}/gradle/publish-root.gradle"
 
 allprojects {
@@ -14,7 +12,7 @@ allprojects {
 
     java {
         toolchain {
-            languageVersion = JavaLanguageVersion.of(javaVersion)
+            languageVersion = JavaLanguageVersion.of(libs.versions.java.get())
         }
     }
 

gradle/libs.versions.toml

@@ -1,4 +1,5 @@
 [versions]
+java = "21"
 spring-boot = "3.4.0"
 spring-dependency-management = "1.1.6"
 openapi-generator = "7.10.0"