Build javadoc with JDK 17 to fix #2429 (#2445)

Co-authored-by: liach <7806504+liach@users.noreply.github.com>

.github/workflows/build.yml

@@ -12,9 +12,12 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: gradle/wrapper-validation-action@v1
-      - run: ./gradlew build javadocJar checkMappings --stacktrace
+      - run: |
+          curl https://maven.fabricmc.net/net/java/jdk/openjdk-17-ea%2B24_linux-x64_bin.tar.gz --output java.tar.gz
+          tar -xf java.tar.gz
+      - run: ./gradlew build javadocJar checkMappings --stacktrace -Porg.gradle.java.installations.auto-download=false -Porg.gradle.java.installations.paths=$(pwd)/jdk-17
       - name: Build artifacts
-        if: ${{ matrix.java == '15-jdk' }}
+        if: ${{ matrix.java == '16-jdk' }}
         continue-on-error: true
         uses: actions/upload-artifact@v2
         with:

.github/workflows/publish.yml

@@ -28,7 +28,10 @@ jobs:
           token: ${{ secrets.github_token }}
           prefix: ${{ github.ref }}
 
-      - run: ./gradlew build javadocJar checkVersion publish --stacktrace
+      - run: |
+          curl https://maven.fabricmc.net/net/java/jdk/openjdk-17-ea%2B24_linux-x64_bin.tar.gz --output java.tar.gz
+          tar -xf java.tar.gz
+      - run: ./gradlew build javadocJar checkVersion publish --stacktrace -Porg.gradle.java.installations.auto-download=false -Porg.gradle.java.installations.paths=$(pwd)/jdk-17
         env:
           MAVEN_URL: ${{ secrets.MAVEN_URL }}
           MAVEN_USERNAME: ${{ secrets.MAVEN_USERNAME }}

build.gradle

@@ -833,6 +833,13 @@ javadoc {
 	group = "javadoc generation"
 	outputs.upToDateWhen { false }
 
+	if (ENV.CI) {
+		// Java 17 is provided on CI to build the javadocs with, see https://github.com/FabricMC/yarn/issues/2429
+		javadocTool = javaToolchains.javadocToolFor {
+			languageVersion = JavaLanguageVersion.of(17)
+		}
+	}
+
 	def mappingPoetJar = project.provider { zipTree configurations.mappingPoetJar.singleFile }
 
 	failOnError = false