Bump JDK version requirement in Gradle and CI

.github/workflows/ci.yml

@@ -29,29 +29,29 @@ jobs:
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v5
 
-      - name: Run unit tests
+      - name: Run unit tests (Java 23)
         env:
           USER: unittest
           USE_DOCKER_SERVICE: false
-        run: ./gradlew --no-daemon test -x spotlessCheck -x spotlessApply -x spotlessJava -P edgeDepsTest
+        run: ./gradlew --no-daemon test -x spotlessCheck -x spotlessApply -x spotlessJava -P edgeDepsTest -PtestJavaVersion=23
 
       - name: Run independent resource tuner test
         env:
           USER: unittest
           USE_DOCKER_SERVICE: false
-        run: ./gradlew --no-daemon temporal-sdk:testResourceIndependent -x spotlessCheck -x spotlessApply -x spotlessJava -P edgeDepsTest
+        run: ./gradlew --no-daemon temporal-sdk:testResourceIndependent -x spotlessCheck -x spotlessApply -x spotlessJava -P edgeDepsTest -PtestJavaVersion=23
 
       - name: Run Spring Boot 3 compatibility tests
         env:
           USER: unittest
           USE_DOCKER_SERVICE: false
-        run: ./gradlew --no-daemon :temporal-spring-boot-autoconfigure:test -x spotlessCheck -x spotlessApply -x spotlessJava -P edgeDepsTest -P springBoot3Test
+        run: ./gradlew --no-daemon :temporal-spring-boot-autoconfigure:test -x spotlessCheck -x spotlessApply -x spotlessJava -P edgeDepsTest -P springBoot3Test -PtestJavaVersion=23
 
       - name: Run Spring Boot 4 compatibility tests
         env:
           USER: unittest
           USE_DOCKER_SERVICE: false
-        run: ./gradlew --no-daemon :temporal-spring-boot-autoconfigure:test -x spotlessCheck -x spotlessApply -x spotlessJava -P edgeDepsTest -P springBoot4Test
+        run: ./gradlew --no-daemon :temporal-spring-boot-autoconfigure:test -x spotlessCheck -x spotlessApply -x spotlessJava -P edgeDepsTest -P springBoot4Test -PtestJavaVersion=23
 
       - name: Publish Test Report
         uses: mikepenz/action-junit-report@v6
@@ -75,8 +75,8 @@ jobs:
         uses: actions/setup-java@v5
         with:
           java-version: |
-            23
             11
+            23
           distribution: "temurin"
 
       - name: Set up Gradle
@@ -113,25 +113,29 @@ jobs:
               --dynamic-config-value 'component.callbacks.allowedAddresses=[{"Pattern":"localhost:7243","AllowInsecure":true}]' &
           sleep 10s
 
-      - name: Run unit tests
+      # Can't actually run tests against Java 8 because Mockito 5 requires Java 11+.
+      # We therefore have to rely on the fact that the code has been compiled with
+      # `-release 8` which guarantees that the code is technically (bytecode + API
+      # usage) compatible with Java 8.
+      - name: Run unit tests (Java 11)
         env:
           USER: unittest
           TEMPORAL_SERVICE_ADDRESS: localhost:7233
           USE_DOCKER_SERVICE: true
-        run: ./gradlew --no-daemon test -x spotlessCheck -x spotlessApply -x spotlessJava
+        run: ./gradlew --no-daemon test -x spotlessCheck -x spotlessApply -x spotlessJava -PtestJavaVersion=11
 
-      - name: Run Jackson 3 converter tests
+      - name: Run Jackson 3 converter tests (Java 17)
         env:
           USER: unittest
           USE_DOCKER_SERVICE: false
-        run: ./gradlew --no-daemon :temporal-sdk:jackson3Tests -x spotlessCheck -x spotlessApply -x spotlessJava
+        run: ./gradlew --no-daemon :temporal-sdk:jackson3Tests -x spotlessCheck -x spotlessApply -x spotlessJava -PtestJavaVersion=17
 
-      - name: Run virtual thread tests
+      - name: Run virtual thread tests (Java 21)
         env:
           USER: unittest
           TEMPORAL_SERVICE_ADDRESS: localhost:7233
           USE_DOCKER_SERVICE: true
-        run: ./gradlew --no-daemon :temporal-sdk:virtualThreadTests -x spotlessCheck -x spotlessApply -x spotlessJava
+        run: ./gradlew --no-daemon :temporal-sdk:virtualThreadTests -x spotlessCheck -x spotlessApply -x spotlessJava -PtestJavaVersion=21
 
       - name: Publish Test Report
         uses: mikepenz/action-junit-report@v6
@@ -154,7 +158,7 @@ jobs:
       - name: Set up Java
         uses: actions/setup-java@v5
         with:
-          java-version: "11"
+          java-version: "23"
           distribution: "temurin"
 
       - name: Set up Gradle

.github/workflows/coverage.yml

@@ -19,14 +19,14 @@ jobs:
       - name: Set up Java
         uses: actions/setup-java@v5
         with:
-          java-version: '11'
-          distribution: 'temurin'
+          java-version: "23"
+          distribution: "temurin"
 
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v5
 
       - name: Run Tests
-        run: ./gradlew test -x spotlessCheck -x spotlessApply -Pjacoco
+        run: ./gradlew test -x spotlessCheck -x spotlessApply -Pjacoco -PtestJavaVersion=23
         continue-on-error: true
 
       - name: Run Test Coverage

.github/workflows/nightly-throughput-stress.yml

@@ -89,14 +89,14 @@ jobs:
       - name: Set up Java
         uses: actions/setup-java@v5
         with:
-          java-version: "11"
+          java-version: "23"
           distribution: "temurin"
 
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v4
 
       - name: Build SDK
-        run: ./gradlew build -x test -x virtualThreadTests
+        run: ./gradlew build -x test -x virtualThreadTests -PtestJavaVersion=23
 
       - name: Install Temporal CLI
         uses: temporalio/setup-temporal@v0

.github/workflows/prepare-release.yml

@@ -94,7 +94,7 @@ jobs:
       - name: Set up Java
         uses: actions/setup-java@v5
         with:
-          java-version: "11"
+          java-version: "23"
           distribution: "temurin"
 
       - name: Set up Gradle

.github/workflows/publish-snapshot.yml

@@ -38,7 +38,7 @@ jobs:
       - name: Set up Java
         uses: actions/setup-java@v5
         with:
-          java-version: '11'
+          java-version: '23'
           distribution: 'temurin'
 
       - name: Set up Gradle

CONTRIBUTING.md

@@ -2,14 +2,14 @@
 
 This doc is intended for contributors to `sdk-java` (hopefully that's you!)
 
-**Note:** All contributors also need to fill out the 
-[Temporal Contributor License Agreement](https://gist.github.com/samarabbas/7dcd41eb1d847e12263cc961ccfdb197) 
+**Note:** All contributors also need to fill out the
+[Temporal Contributor License Agreement](https://gist.github.com/samarabbas/7dcd41eb1d847e12263cc961ccfdb197)
 before we can merge in any of your changes
 
 ## Development Environment
 
-* Java 21+
-* Docker to run Temporal Server
+- Java 23+
+- Docker to run Temporal Server
 
 ## Build
 
@@ -31,13 +31,15 @@ commit messages. Read it, follow it, learn it, love it.
 ## Running features tests in CI
 
 For each PR we run the java tests from the [features repo](https://github.com/temporalio/features/). This requires
-your branch to have tags. Without tags, the features tests in CI will fail with a message like 
+your branch to have tags. Without tags, the features tests in CI will fail with a message like
+
 ```
 > Configure project :sdk-java
 fatal: No names found, cannot describe anything.
 ```
+
 This can be done resolved by running `git fetch --tags` on your branch. Note, make sure your fork has tags copied from
-the main repo. 
+the main repo.
 
 ## Test and Build
 
@@ -62,6 +64,7 @@ Build with:
 ```
 
 ## Note on Rosetta
+
 Newer Apple Silicon macs do not ship with Rosetta by default, and the version of `protoc-gen-rpc-java` we use (1.34.1) does not ship Apple Silicon binaries.
 
 So Gradle is set to hardcode the download of the x86_64 binaries on MacOS, but this depends on Rosetta to function. Make sure Rosetta is installed with

build.gradle

@@ -1,12 +1,5 @@
-buildscript {
-    ext {
-        palantirGitVersionVersion = "${JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_11) ? '0.15.0' : '0.13.0'}"
-    }
-}
-
 plugins {
     id 'net.ltgt.errorprone' version '4.1.0' apply false
-    id 'com.palantir.git-version' version "${palantirGitVersionVersion}" apply false
     id 'io.github.gradle-nexus.publish-plugin' version '1.3.0'
     id 'com.diffplug.spotless' version '7.0.2' apply false
     id 'com.github.nbaztec.coveralls-jacoco' version "1.2.20" apply false
@@ -79,9 +72,7 @@ ext {
 
 apply from: "$rootDir/gradle/versioning.gradle"
 apply from: "$rootDir/gradle/java.gradle"
-if (JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_11)) {
-    apply from: "$rootDir/gradle/linting.gradle"
-}
+apply from: "$rootDir/gradle/linting.gradle"
 apply from: "$rootDir/gradle/errorprone.gradle"
 apply from: "$rootDir/gradle/publishing.gradle"
 apply from: "$rootDir/gradle/dependencyManagement.gradle"

gradle/java.gradle

@@ -15,7 +15,7 @@ subprojects {
     compileJava {
         options.encoding = 'UTF-8'
         options.compilerArgs << '-Xlint:none' << '-Xlint:deprecation' << '-Werror' << '-parameters'
-        if (JavaVersion.current().isJava9Compatible() && !project.hasProperty("edgeDepsTest") && !project.hasProperty("nativeBuild")) {
+        if (!project.hasProperty("edgeDepsTest") && !project.hasProperty("nativeBuild")) {
             // https://stackoverflow.com/a/43103115/525203
             options.compilerArgs.addAll(['--release', '8'])
         }
@@ -24,7 +24,7 @@ subprojects {
     compileTestJava {
         options.encoding = 'UTF-8'
         options.compilerArgs << '-Xlint:none' << '-Xlint:deprecation' << '-Werror' << '-parameters'
-        if (JavaVersion.current().isJava9Compatible() && !project.hasProperty("edgeDepsTest") && !project.hasProperty("nativeBuild")) {
+        if (!project.hasProperty("edgeDepsTest") && !project.hasProperty("nativeBuild")) {
             // https://stackoverflow.com/a/43103115/525203
             options.compilerArgs.addAll(['--release', '8'])
         }
@@ -34,21 +34,19 @@ subprojects {
         options.encoding = 'UTF-8'
         options.addStringOption('Xdoclint:reference', '-quiet')
         options.addBooleanOption('Werror', true)
-        if (JavaVersion.current().isJava9Compatible()) {
-            options.addBooleanOption('html5', true)
-        }
-        if (JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_1_9) &&
-                !JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_13)) {
-            //https://stackoverflow.com/questions/53732632/gradle-javadoc-search-redirects-to-undefined-url
-            //the flag is removed in java13: https://bugs.openjdk.java.net/browse/JDK-8215582
-            options.addBooleanOption('-no-module-directories', true)
-        }
+        options.addBooleanOption('html5', true)
     }
 
     // add a collection to track failedTests
     ext.failedTests = []
 
     test {
+        if (project.hasProperty("testJavaVersion")) {
+            javaLauncher = javaToolchains.launcherFor {
+                languageVersion = JavaLanguageVersion.of(project.property("testJavaVersion") as int)
+            }
+        }
+
         testLogging {
             events 'passed', 'skipped', 'failed'
             exceptionFormat 'full'

mise.toml

@@ -0,0 +1,15 @@
+# TIP 
+# 
+# For the best SDK development experience, make to hava all of the following
+# JDKs installed on your machine (`mise install java@[version]`):
+#   - `java@temurin-11`
+#   - `java@temurin-17`
+#   - `java@temurin-23`
+# 
+# Java 21+ is required for anything that requires gradle.
+# 
+# If you find out that gradle isn't automatically picking it up older JDKs as
+# toolchains, see https://mise.jdx.dev/lang/java.html#gradle-toolchains-detection.
+
+[tools]
+java = "temurin-23"

temporal-kotlin/build.gradle

@@ -12,7 +12,7 @@ tasks.withType(KotlinCompile).all {
     kotlinOptions {
         freeCompilerArgs += "-Xopt-in=kotlin.RequiresOptIn"
         jvmTarget = project.hasProperty("edgeDepsTest") ? JavaVersion.VERSION_21 : JavaVersion.VERSION_1_8
-        languageVersion = "${project.hasProperty("edgeDepsTest") ? '1.8' : (JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_16) ? '1.5' : '1.4')}"
+        languageVersion = "${project.hasProperty("edgeDepsTest") ? '1.8' : '1.5'}"
     }
 }
 

temporal-sdk/build.gradle

@@ -66,28 +66,10 @@ dependencies {
 }
 
 tasks.named('compileJava17Java') {
-    // Gradle toolchains are too strict and require the JDK to match the specified version exactly.
-    // This is a workaround to use a JDK 17+ compiler.
-    //
-    // See also: https://github.com/gradle/gradle/issues/16256
-    if (!JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_17)) {
-        javaCompiler = javaToolchains.compilerFor {
-            languageVersion = JavaLanguageVersion.of(17)
-        }
-    }
     options.release = 17
 }
 
 tasks.named('compileJava21Java') {
-    // Gradle toolchains are too strict and require the JDK to match the specified version exactly.
-    // This is a workaround to use a JDK 21+ compiler.
-    //
-    // See also: https://github.com/gradle/gradle/issues/16256
-    if (!JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_21)) {
-        javaCompiler = javaToolchains.compilerFor {
-            languageVersion = JavaLanguageVersion.of(21)
-        }
-    }
     options.release = 21
 }
 
@@ -142,9 +124,7 @@ test {
 // the present-java17-but-absent-jackson3 behavior (NoClassDefFoundError) in the same
 // test that tests the Java 8 stub behavior (UnsupportedOperationException).
 tasks.withType(Test).configureEach {
-    if (JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_17)) {
-        dependsOn compileJava17Java
-    }
+    dependsOn compileJava17Java
     doFirst {
         int launcherMajorVersion = javaLauncher.get().metadata.languageVersion.asInt()
         if (launcherMajorVersion >= 17) {

temporal-workflowcheck/samples/gradle/build.gradle

@@ -29,10 +29,10 @@ dependencies {
 tasks.register('workflowcheck', JavaExec) {
     // Set the classpath to the workflowcheck dependency
     classpath = configurations.workflowcheckDependency
-    // // Java 17+ is required for workflowcheck
-    // javaLauncher = javaToolchains.launcherFor {
-    //     languageVersion = JavaLanguageVersion.of(17)
-    // }
+    // Java 17+ is required for workflowcheck
+    javaLauncher = javaToolchains.launcherFor {
+        languageVersion = JavaLanguageVersion.of(17)
+    }
     // The argument to workflowcheck is the classpath
     mainClass = 'io.temporal.workflowcheck.Main'
     args = ['check', sourceSets.main.runtimeClasspath.files.join(File.pathSeparator)]