Use JDK 24 and enable NullAway's JSpecify mode

.github/actions/run-gradle/action.yml

@@ -15,7 +15,7 @@ runs:
       id: setup-gradle-jdk
       with:
         distribution: temurin
-        java-version: 21
+        java-version: 24
         check-latest: true
     - uses: gradle/actions/setup-gradle@8379f6a1328ee0e06e2bb424dadb7b159856a326 # v4.4.0
       with:

.github/workflows/cross-version.yml

@@ -22,8 +22,6 @@ jobs:
       fail-fast: false
       matrix:
         jdk:
-        - version: 24
-          type: ga
         - version: 25
           type: ea
     name: "OpenJDK ${{ matrix.jdk.version }} (${{ matrix.jdk.release || matrix.jdk.type }})"

.github/workflows/gradle-dependency-submission.yml

@@ -22,7 +22,7 @@ jobs:
       uses: actions/setup-java@c5195efecf7bdfc987ee8bae7a71cb8b11521c00 # v4.7.1
       with:
         distribution: temurin
-        java-version: 21
+        java-version: 24
         check-latest: true
     - name: Generate and submit dependency graph
       uses: gradle/actions/dependency-submission@8379f6a1328ee0e06e2bb424dadb7b159856a326 # v4.4.0

.github/workflows/main.yml

@@ -29,7 +29,7 @@ jobs:
       with:
         distribution: graalvm-community
         version: 'latest'
-        java-version: '21'
+        java-version: '24'
         github-token: ${{ secrets.GITHUB_TOKEN }}
     - name: Build
       uses: ./.github/actions/main-build

.github/workflows/release.yml

@@ -87,7 +87,7 @@ jobs:
       - name: Set up JDK
         uses: actions/setup-java@c5195efecf7bdfc987ee8bae7a71cb8b11521c00 # v4.7.1
         with:
-          java-version: 21
+          java-version: 24
           distribution: temurin
       - uses: sbt/setup-sbt@69a46ab4acd4316aa16e68d91a9249a98d7e78d5 # v1.1.8
       - name: Update JUnit dependencies in samples
@@ -245,7 +245,7 @@ jobs:
       - name: Set up JDK
         uses: actions/setup-java@c5195efecf7bdfc987ee8bae7a71cb8b11521c00 # v4.7.1
         with:
-          java-version: 21
+          java-version: 24
           distribution: temurin
       - uses: sbt/setup-sbt@69a46ab4acd4316aa16e68d91a9249a98d7e78d5 # v1.1.8
       - name: Update JUnit dependencies in samples

README.md

@@ -70,7 +70,7 @@ task outputs from previous CI builds.
 
 ## Building from Source
 
-You need [JDK 21] to build JUnit. [Gradle toolchains] are used to detect and
+You need [JDK 24] to build JUnit. [Gradle toolchains] are used to detect and
 potentially download additional JDKs for compilation and test execution.
 
 All modules can be _built_ and _tested_ with the [Gradle Wrapper] using the following command:
@@ -100,7 +100,7 @@ of the JUnit Platform, JUnit Jupiter, and JUnit Vintage.
 [Gradle Wrapper]: https://docs.gradle.org/current/userguide/gradle_wrapper.html#sec:using_wrapper
 [JaCoCo]: https://www.eclemma.org/jacoco/
 [Javadoc]: https://junit.org/junit5/docs/current/api/
-[JDK 21]: https://javaalmanac.io/jdk/21/
+[JDK 24]: https://javaalmanac.io/jdk/24/
 [Release Notes]: https://junit.org/junit5/docs/current/release-notes/
 [Samples]: https://github.com/junit-team/junit5-samples
 [StackOverflow]: https://stackoverflow.com/questions/tagged/junit5

documentation/src/docs/asciidoc/release-notes/release-notes-6.0.0-M1.adoc

@@ -76,6 +76,11 @@ repository on GitHub.
   property has been removed. JUnit now always adheres to standard Java semantics regarding
   whether a given field or method is visible or overridden according to the rules of the
   Java language.
+* The type bounds of the following methods have been changed to be more flexible and allow
+  nullable and non-nullable types:
+  - `ConfigurationParameters.get(String, Function)`
+  - `NamespacedHierarchicalStore.getOrComputeIfAbsent(N, K, Function)`
+  - `NamespacedHierarchicalStore.getOrComputeIfAbsent(N, K, Function, Class)`
 
 [[release-notes-6.0.0-M1-junit-platform-new-features-and-improvements]]
 ==== New Features and Improvements
@@ -112,6 +117,11 @@ repository on GitHub.
   `callsInPlace(executable, AT_MOST_ONCE)` which might result in compilation errors.
 * The `junit-jupiter-migrationsupport` artifact and its contained classes are now
   deprecated and will be removed in the next major version.
+* The type bounds of the following methods have been changed to be more flexible and allow
+  nullable and non-nullable types:
+  - `ExtensionContext.getConfigurationParameter(String, Function)`
+  - `ExtensionContext.getOrComputeIfAbsent(K, Function)`
+  - `ExtensionContext.getOrComputeIfAbsent(K, Function, Class)`
 
 [[release-notes-6.0.0-M1-junit-jupiter-new-features-and-improvements]]
 ==== New Features and Improvements

documentation/src/javadoc/junit-stylesheet.css

@@ -30,6 +30,9 @@
     /* Text colors for links */
     --link-color: #dc524a;
     --link-color-active: #b62b23;
+    /* Table of contents */
+    --toc-background-color: var(--section-background-color);
+    --toc-link-color: #000;
     /* Snippet colors */
     --snippet-background-color: #ebecee;
     --snippet-text-color: var(--block-text-color);
@@ -39,10 +42,6 @@
     --table-border-color: #999;
     /* Highlight color for active search tag target */
     --search-tag-highlight-color: #ffff00;
-    /* Adjustments for icon and active background colors of copy-to-clipboard buttons */
-    --copy-button-background-color-active: rgba(168, 168, 168, 0.3);
-    /* Colors for invalid tag notifications */
-    --invalid-tag-background-color: #ffe6e6;
 }
 
 .title {

documentation/src/test/java/example/FirstCustomEngine.java

@@ -48,6 +48,9 @@ public TestDescriptor discover(EngineDiscoveryRequest discoveryRequest, UniqueId
 		return new EngineDescriptor(uniqueId, "First Custom Test Engine");
 	}
 
+	//end::user_guide[]
+	@SuppressWarnings("NullAway")
+	//tag::user_guide[]
 	@Override
 	public void execute(ExecutionRequest request) {
 		request.getEngineExecutionListener()

documentation/src/test/java/example/ParameterizedLifecycleDemo.java

@@ -55,7 +55,7 @@ static void beforeInvocation(TextFile textFile, @TempDir Path tempDir) throws Ex
 		}
 
 		//end::user_guide[]
-		@SuppressWarnings({ "DataFlowIssue", "NullAway" })
+		@SuppressWarnings("DataFlowIssue")
 		//tag::user_guide[]
 		@AfterParameterizedClassInvocation
 		static void afterInvocation(TextFile textFile) throws Exception {
@@ -66,7 +66,7 @@ static void afterInvocation(TextFile textFile) throws Exception {
 		}
 
 		//end::user_guide[]
-		@SuppressWarnings({ "DataFlowIssue", "NullAway" })
+		@SuppressWarnings("DataFlowIssue")
 		//tag::user_guide[]
 		@Test
 		void test() {

documentation/src/test/java/example/SecondCustomEngine.java

@@ -48,6 +48,9 @@ public TestDescriptor discover(EngineDiscoveryRequest discoveryRequest, UniqueId
 		return new EngineDescriptor(uniqueId, "Second Custom Test Engine");
 	}
 
+	//end::user_guide[]
+	@SuppressWarnings("NullAway")
+	//tag::user_guide[]
 	@Override
 	public void execute(ExecutionRequest request) {
 		request.getEngineExecutionListener()

documentation/src/test/java/example/interceptor/SwingEdtInterceptor.java

@@ -23,6 +23,9 @@
 // tag::user_guide[]
 public class SwingEdtInterceptor implements InvocationInterceptor {
 
+	//end::user_guide[]
+	@SuppressWarnings("NullAway")
+	//tag::user_guide[]
 	@Override
 	public void interceptTestMethod(Invocation<Void> invocation,
 			ReflectiveInvocationContext<Method> invocationContext,

gradle/base/code-generator-model/build.gradle.kts

@@ -1,4 +1,4 @@
-import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
 
 plugins {
     `kotlin-dsl`
@@ -10,5 +10,8 @@ java {
 }
 
 kotlin {
-    compilerOptions.jvmTarget = JvmTarget.JVM_17
+    compilerOptions {
+        jvmTarget = JVM_17
+        freeCompilerArgs.add("-Xjdk-release=17")
+    }
 }

gradle/base/dsl-extensions/build.gradle.kts

@@ -1,3 +1,16 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_21
+
 plugins {
     `kotlin-dsl`
 }
+
+tasks.compileJava {
+    options.release = 21
+}
+
+kotlin {
+    compilerOptions {
+        jvmTarget = JVM_21
+        freeCompilerArgs.add("-Xjdk-release=21")
+    }
+}

gradle/gradle-daemon-jvm.properties

@@ -1,2 +1,2 @@
 #This file is generated by updateDaemonJvm
-toolchainVersion=21
+toolchainVersion=24

gradle/plugins/build-parameters/build.gradle.kts

@@ -4,6 +4,10 @@ plugins {
 
 group = "junitbuild"
 
+tasks.compileJava {
+	options.release = 21
+}
+
 buildParameters {
 	pluginId("junitbuild.build-parameters")
 	bool("ci") {

gradle/plugins/code-generator/build.gradle.kts

@@ -1,3 +1,5 @@
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_21
+
 plugins {
 	`kotlin-dsl`
 }
@@ -10,3 +12,14 @@ dependencies {
 	implementation(libs.jackson.module.kotlin)
 	implementation(libs.jte)
 }
+
+tasks.compileJava {
+	options.release = 21
+}
+
+kotlin {
+	compilerOptions {
+		jvmTarget = JVM_21
+		freeCompilerArgs.add("-Xjdk-release=21")
+	}
+}

gradle/plugins/common/build.gradle.kts

@@ -1,4 +1,5 @@
 import junitbuild.extensions.markerCoordinates
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_21
 
 plugins {
 	`kotlin-dsl`
@@ -19,3 +20,14 @@ dependencies {
 	implementation(libs.plugins.shadow.markerCoordinates)
 	implementation(libs.plugins.spotless.markerCoordinates)
 }
+
+tasks.compileJava {
+	options.release = 21
+}
+
+kotlin {
+	compilerOptions {
+		jvmTarget = JVM_21
+		freeCompilerArgs.add("-Xjdk-release=21")
+	}
+}

gradle/plugins/common/src/main/kotlin/junitbuild.java-nullability-conventions.gradle.kts

@@ -21,7 +21,12 @@ tasks.withType<JavaCompile>().configureEach {
 	options.errorprone {
 		disableAllChecks = true
 		nullaway {
-			enable()
+			if (java.toolchain.implementation.orNull == JvmImplementation.J9) {
+				disable()
+			} else {
+				enable()
+			}
+			isJSpecifyMode = true
 		}
 	}
 }

gradle/plugins/common/src/main/kotlin/junitbuild.java-toolchain-conventions.gradle.kts

@@ -5,7 +5,7 @@ plugins {
 }
 
 project.pluginManager.withPlugin("java") {
-	val defaultLanguageVersion = JavaLanguageVersion.of(21)
+	val defaultLanguageVersion = JavaLanguageVersion.of(24)
 	val javaLanguageVersion = buildParameters.javaToolchain.version.map { JavaLanguageVersion.of(it) }.getOrElse(defaultLanguageVersion)
 	val jvmImplementation = buildParameters.javaToolchain.implementation.map {
 		when(it) {

gradle/plugins/common/src/main/kotlin/junitbuild.kotlin-library-conventions.gradle.kts

@@ -1,3 +1,4 @@
+
 import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 import org.jetbrains.kotlin.gradle.dsl.KotlinVersion.KOTLIN_2_1
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
@@ -20,7 +21,8 @@ tasks.withType<KotlinCompile>().configureEach {
 		languageVersion = apiVersion
 		allWarningsAsErrors.convention(true)
 		javaParameters = true
-		freeCompilerArgs.addAll("-opt-in=kotlin.RequiresOptIn")
+		freeCompilerArgs.add("-opt-in=kotlin.RequiresOptIn")
+		freeCompilerArgs.add(jvmTarget.map { "-Xjdk-release=${JavaVersion.toVersion(it.target).majorVersion}" })
 	}
 }
 

gradle/plugins/common/src/main/kotlin/junitbuild.testing-conventions.gradle.kts

@@ -110,6 +110,8 @@ tasks.withType<Test>().configureEach {
 	systemProperty("log4j2.julLoggerAdapter", "org.apache.logging.log4j.jul.CoreLoggerAdapter")
 	// Avoid overhead (see https://logging.apache.org/log4j/2.x/manual/jmx.html#enabling-jmx)
 	systemProperty("log4j2.disableJmx", "true")
+	// https://github.com/raphw/byte-buddy/issues/1803
+	systemProperty("net.bytebuddy.safe", true)
 	// Required until ASM officially supports the JDK 14
 	systemProperty("net.bytebuddy.experimental", true)
 	if (buildParameters.testing.enableJFR) {

gradle/plugins/publishing/build.gradle.kts

@@ -1,4 +1,5 @@
 import junitbuild.extensions.markerCoordinates
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_21
 
 plugins {
 	`kotlin-dsl`
@@ -23,3 +24,14 @@ configurations.configureEach {
 		}
 	}
 }
+
+tasks.compileJava {
+	options.release = 21
+}
+
+kotlin {
+	compilerOptions {
+		jvmTarget = JVM_21
+		freeCompilerArgs.add("-Xjdk-release=21")
+	}
+}

junit-jupiter-api/src/main/java/org/junit/jupiter/api/AssertTimeout.java

@@ -36,17 +36,15 @@ static void assertTimeout(Duration timeout, Executable executable) {
 		assertTimeout(timeout, executable, (String) null);
 	}
 
-	@SuppressWarnings("NullAway")
 	static void assertTimeout(Duration timeout, Executable executable, @Nullable String message) {
-		assertTimeout(timeout, () -> {
+		AssertTimeout.<@Nullable Object> assertTimeout(timeout, () -> {
 			executable.execute();
 			return null;
 		}, message);
 	}
 
-	@SuppressWarnings("NullAway")
 	static void assertTimeout(Duration timeout, Executable executable, Supplier<@Nullable String> messageSupplier) {
-		assertTimeout(timeout, () -> {
+		AssertTimeout.<@Nullable Object> assertTimeout(timeout, () -> {
 			executable.execute();
 			return null;
 		}, messageSupplier);

junit-jupiter-api/src/main/java/org/junit/jupiter/api/AssertionFailureBuilder.java

@@ -32,22 +32,17 @@
 @API(status = STABLE, since = "5.9")
 public class AssertionFailureBuilder {
 
-	@Nullable
-	private Object message;
+	private @Nullable Object message;
 
-	@Nullable
-	private Throwable cause;
+	private @Nullable Throwable cause;
 
 	private boolean mismatch;
 
-	@Nullable
-	private Object expected;
+	private @Nullable Object expected;
 
-	@Nullable
-	private Object actual;
+	private @Nullable Object actual;
 
-	@Nullable
-	private String reason;
+	private @Nullable String reason;
 
 	private boolean includeValuesInMessage = true;
 

junit-jupiter-api/src/main/java/org/junit/jupiter/api/DynamicNode.java

@@ -34,8 +34,7 @@ public abstract class DynamicNode {
 	private final String displayName;
 
 	/** Custom test source {@link URI} associated with this node; potentially {@code null}. */
-	@Nullable
-	private final URI testSourceUri;
+	private final @Nullable URI testSourceUri;
 
 	DynamicNode(String displayName, @Nullable URI testSourceUri) {
 		this.displayName = Preconditions.notBlank(displayName, "displayName must not be null or blank");

junit-jupiter-api/src/main/java/org/junit/jupiter/api/condition/OS.java

@@ -95,8 +95,7 @@ public enum OS {
 
 	private static final Logger logger = LoggerFactory.getLogger(OS.class);
 
-	@Nullable
-	private static final OS CURRENT_OS = determineCurrentOs();
+	private static final @Nullable OS CURRENT_OS = determineCurrentOs();
 
 	/**
 	 * {@return the current operating system, if known; otherwise, {@code null}}