Use Java 9-17 APIs and patterns

documentation/src/test/java/example/ClassTemplateDemo.java

@@ -11,11 +11,9 @@
 package example;
 
 import static java.util.Collections.singletonList;
-import static java.util.Collections.unmodifiableList;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import java.util.Arrays;
 import java.util.List;
 import java.util.stream.Stream;
 
@@ -36,7 +34,7 @@ class ClassTemplateDemo {
 
 	static final List<String> WELL_KNOWN_FRUITS
 	// tag::custom_line_break[]
-		= unmodifiableList(Arrays.asList("apple", "banana", "lemon"));
+		= List.of("apple", "banana", "lemon");
 
 	//end::user_guide[]
 	@Nullable

documentation/src/test/java/example/ExternalFieldSourceDemo.java

@@ -10,8 +10,6 @@
 
 package example;
 
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 
 import org.junit.jupiter.params.ParameterizedTest;
@@ -30,6 +28,6 @@ void testWithExternalFieldSource(String tropicalFruit) {
 
 class FruitUtils {
 
-	public static final List<String> tropicalFruits = Collections.unmodifiableList(Arrays.asList("pineapple", "kiwi"));
+	public static final List<String> tropicalFruits = List.of("pineapple", "kiwi");
 
 }

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

@@ -14,7 +14,6 @@
 import java.util.Collection;
 import java.util.List;
 import java.util.Objects;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import org.jspecify.annotations.Nullable;
@@ -75,7 +74,7 @@ static void assertAll(@Nullable String heading, Stream<Executable> executables)
 					}
 				}) //
 				.filter(Objects::nonNull) //
-				.collect(Collectors.toList());
+				.toList();
 
 		if (!failures.isEmpty()) {
 			MultipleFailuresError multipleFailuresError = new MultipleFailuresError(heading, failures);

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

@@ -198,30 +198,7 @@ private static void failIterablesNotEqual(Object expected, Object actual, Deque<
 				.buildAndThrow();
 	}
 
-	private final static class Pair {
-		private final Object left;
-		private final Object right;
-
-		public Pair(Object left, Object right) {
-			this.left = left;
-			this.right = right;
-		}
-
-		@Override
-		public boolean equals(Object o) {
-			if (this == o)
-				return true;
-			if (o == null || getClass() != o.getClass())
-				return false;
-			Pair that = (Pair) o;
-			return Objects.equals(this.left, that.left) //
-					&& Objects.equals(this.right, that.right);
-		}
-
-		@Override
-		public int hashCode() {
-			return Objects.hash(left, right);
-		}
+	private record Pair(Object left, Object right) {
 	}
 
 	private enum Status {

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

@@ -19,7 +19,6 @@
 import java.util.Deque;
 import java.util.List;
 import java.util.regex.PatternSyntaxException;
-import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
 
@@ -65,8 +64,8 @@ static void assertLinesMatch(Stream<String> expectedLines, Stream<String> actual
 			return;
 		}
 
-		List<String> expectedListOfStrings = expectedLines.collect(Collectors.toList());
-		List<String> actualListOfStrings = actualLines.collect(Collectors.toList());
+		List<String> expectedListOfStrings = expectedLines.toList();
+		List<String> actualListOfStrings = actualLines.toList();
 		assertLinesMatch(expectedListOfStrings, actualListOfStrings, messageOrSupplier);
 	}
 
@@ -83,19 +82,8 @@ static void assertLinesMatch(List<String> expectedLines, List<String> actualLine
 		new LinesMatcher(expectedLines, actualLines, messageOrSupplier).assertLinesMatch();
 	}
 
-	private static class LinesMatcher {
-
-		private final List<String> expectedLines;
-		private final List<String> actualLines;
-
-		@Nullable
-		private final Object messageOrSupplier;
-
-		LinesMatcher(List<String> expectedLines, List<String> actualLines, @Nullable Object messageOrSupplier) {
-			this.expectedLines = expectedLines;
-			this.actualLines = actualLines;
-			this.messageOrSupplier = messageOrSupplier;
-		}
+	private record LinesMatcher(List<String> expectedLines, List<String> actualLines,
+			@Nullable Object messageOrSupplier) {
 
 		void assertLinesMatch() {
 			int expectedSize = expectedLines.size();

junit-jupiter-api/src/main/java/org/junit/jupiter/api/extension/ExtensionContext.java

@@ -10,7 +10,6 @@
 
 package org.junit.jupiter.api.extension;
 
-import static java.util.Collections.unmodifiableList;
 import static org.apiguardian.api.API.Status.DEPRECATED;
 import static org.apiguardian.api.API.Status.EXPERIMENTAL;
 import static org.apiguardian.api.API.Status.INTERNAL;
@@ -20,7 +19,6 @@
 import java.lang.reflect.Method;
 import java.nio.file.Path;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -770,13 +768,13 @@ class Namespace {
 		public static Namespace create(Object... parts) {
 			Preconditions.notEmpty(parts, "parts array must not be null or empty");
 			Preconditions.containsNoNullElements(parts, "individual parts must not be null");
-			return new Namespace(new ArrayList<>(Arrays.asList(parts)));
+			return new Namespace(List.of(parts));
 		}
 
 		private final List<Object> parts;
 
 		private Namespace(List<Object> parts) {
-			this.parts = parts;
+			this.parts = List.copyOf(parts);
 		}
 
 		@Override
@@ -815,7 +813,7 @@ public Namespace append(Object... parts) {
 
 		@API(status = INTERNAL, since = "5.13")
 		public List<Object> getParts() {
-			return unmodifiableList(parts);
+			return parts;
 		}
 	}
 

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/AbstractExtensionContext.java

@@ -221,16 +221,11 @@ public Store getStore(Namespace namespace) {
 
 	@Override
 	public Store getStore(StoreScope scope, Namespace namespace) {
-		// TODO [#4246] Use switch expression
-		switch (scope) {
-			case LAUNCHER_SESSION:
-				return launcherStoreFacade.getSessionLevelStore(namespace);
-			case EXECUTION_REQUEST:
-				return launcherStoreFacade.getRequestLevelStore(namespace);
-			case EXTENSION_CONTEXT:
-				return getStore(namespace);
-		}
-		throw new JUnitException("Unknown StoreScope: " + scope);
+		return switch (scope) {
+			case LAUNCHER_SESSION -> launcherStoreFacade.getSessionLevelStore(namespace);
+			case EXECUTION_REQUEST -> launcherStoreFacade.getRequestLevelStore(namespace);
+			case EXTENSION_CONTEXT -> getStore(namespace);
+		};
 	}
 
 	@Override
@@ -267,12 +262,9 @@ public <E extends Extension> List<E> getExtensions(Class<E> extensionType) {
 	protected abstract Node.ExecutionMode getPlatformExecutionMode();
 
 	private ExecutionMode toJupiterExecutionMode(Node.ExecutionMode mode) {
-		switch (mode) {
-			case CONCURRENT:
-				return ExecutionMode.CONCURRENT;
-			case SAME_THREAD:
-				return ExecutionMode.SAME_THREAD;
-		}
-		throw new JUnitException("Unknown ExecutionMode: " + mode);
+		return switch (mode) {
+			case CONCURRENT -> ExecutionMode.CONCURRENT;
+			case SAME_THREAD -> ExecutionMode.SAME_THREAD;
+		};
 	}
 }

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/ClassTemplateTestDescriptor.java

@@ -11,7 +11,6 @@
 package org.junit.jupiter.engine.descriptor;
 
 import static java.util.stream.Collectors.toCollection;
-import static java.util.stream.Collectors.toList;
 import static org.apiguardian.api.API.Status.INTERNAL;
 import static org.junit.jupiter.api.TestInstance.Lifecycle.PER_METHOD;
 import static org.junit.jupiter.engine.descriptor.LifecycleMethodUtils.validateClassTemplateInvocationLifecycleMethodsAreDeclaredCorrectly;
@@ -108,9 +107,9 @@ protected JupiterTestDescriptor copyIncludingDescendants(UnaryOperator<UniqueId>
 			copy.childrenPrototypes.add(newChild);
 		});
 		this.childrenPrototypesByIndex.forEach((index, oldChildren) -> {
-			List<TestDescriptor> newChildren = oldChildren.stream() //
+			List<? extends TestDescriptor> newChildren = oldChildren.stream() //
 					.map(oldChild -> ((JupiterTestDescriptor) oldChild).copyIncludingDescendants(uniqueIdTransformer)) //
-					.collect(toList());
+					.toList();
 			copy.childrenPrototypesByIndex.put(index, newChildren);
 		});
 		return copy;

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/DefaultDynamicTestInvocationContext.java

@@ -18,13 +18,7 @@
  *
  * @since 5.8
  */
-class DefaultDynamicTestInvocationContext implements DynamicTestInvocationContext {
-
-	private final Executable executable;
-
-	DefaultDynamicTestInvocationContext(Executable executable) {
-		this.executable = executable;
-	}
+record DefaultDynamicTestInvocationContext(Executable executable) implements DynamicTestInvocationContext {
 
 	@Override
 	public Executable getExecutable() {

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/DefaultTestInstanceFactoryContext.java

@@ -20,15 +20,8 @@
  *
  * @since 5.3
  */
-class DefaultTestInstanceFactoryContext implements TestInstanceFactoryContext {
-
-	private final Class<?> testClass;
-	private final Optional<Object> outerInstance;
-
-	DefaultTestInstanceFactoryContext(Class<?> testClass, Optional<Object> outerInstance) {
-		this.testClass = testClass;
-		this.outerInstance = outerInstance;
-	}
+record DefaultTestInstanceFactoryContext(Class<?> testClass, Optional<Object> outerInstance)
+		implements TestInstanceFactoryContext {
 
 	@Override
 	public Class<?> getTestClass() {

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/DisplayNameUtils.java

@@ -10,8 +10,6 @@
 
 package org.junit.jupiter.engine.descriptor;
 
-import static java.util.Collections.emptyList;
-import static java.util.Collections.unmodifiableList;
 import static org.junit.platform.commons.support.AnnotationSupport.findAnnotation;
 
 import java.lang.reflect.AnnotatedElement;
@@ -126,18 +124,14 @@ private static Supplier<String> createDisplayNameSupplier(Supplier<List<Class<?>
 			Class<?> testClass, JupiterConfiguration configuration,
 			BiFunction<DisplayNameGenerator, List<Class<?>>, String> generatorFunction) {
 		return () -> {
-			List<Class<?>> enclosingInstanceTypes = makeUnmodifiable(enclosingInstanceTypesSupplier.get());
+			List<Class<?>> enclosingInstanceTypes = List.copyOf(enclosingInstanceTypesSupplier.get());
 			return findDisplayNameGenerator(enclosingInstanceTypes, testClass) //
 					.map(it -> generatorFunction.apply(it, enclosingInstanceTypes)) //
 					.orElseGet(() -> generatorFunction.apply(configuration.getDefaultDisplayNameGenerator(),
 						enclosingInstanceTypes));
 		};
 	}
 
-	private static <T> List<T> makeUnmodifiable(List<T> list) {
-		return list.isEmpty() ? emptyList() : unmodifiableList(list);
-	}
-
 	private static Optional<DisplayNameGenerator> findDisplayNameGenerator(List<Class<?>> enclosingInstanceTypes,
 			Class<?> testClass) {
 		Preconditions.notNull(testClass, "Test class must not be null");

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/ExclusiveResourceCollector.java

@@ -12,7 +12,6 @@
 
 import static org.junit.jupiter.api.parallel.ResourceLockTarget.SELF;
 import static org.junit.platform.commons.support.AnnotationSupport.findRepeatableAnnotations;
-import static org.junit.platform.commons.util.CollectionUtils.toUnmodifiableList;
 
 import java.lang.reflect.AnnotatedElement;
 import java.util.Collection;
@@ -26,7 +25,6 @@
 import org.junit.jupiter.api.parallel.ResourceLock;
 import org.junit.jupiter.api.parallel.ResourceLockTarget;
 import org.junit.jupiter.api.parallel.ResourceLocksProvider;
-import org.junit.platform.commons.JUnitException;
 import org.junit.platform.commons.util.ReflectionUtils;
 import org.junit.platform.commons.util.StringUtils;
 import org.junit.platform.engine.support.hierarchical.ExclusiveResource;
@@ -106,20 +104,21 @@ Stream<ExclusiveResource> getDynamicResources(
 		private List<ResourceLocksProvider> getProviders() {
 			if (this.providers == null) {
 				this.providers = annotations.stream() //
-						.flatMap(annotation -> Stream.of(annotation.providers()).map(ReflectionUtils::newInstance)) //
-						.collect(toUnmodifiableList());
+						.flatMap(annotation -> instantiate(annotation.providers())) //
+						.toList();
 			}
 			return providers;
 		}
 
+		private static Stream<ResourceLocksProvider> instantiate(Class<? extends ResourceLocksProvider>[] providers) {
+			return Stream.of(providers).map(ReflectionUtils::newInstance);
+		}
+
 		private static ExclusiveResource.LockMode toLockMode(ResourceAccessMode mode) {
-			switch (mode) {
-				case READ:
-					return ExclusiveResource.LockMode.READ;
-				case READ_WRITE:
-					return ExclusiveResource.LockMode.READ_WRITE;
-			}
-			throw new JUnitException("Unknown ResourceAccessMode: " + mode);
+			return switch (mode) {
+				case READ -> ExclusiveResource.LockMode.READ;
+				case READ_WRITE -> ExclusiveResource.LockMode.READ_WRITE;
+			};
 		}
 	}
 }

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/JupiterTestDescriptor.java

@@ -41,7 +41,6 @@
 import org.junit.jupiter.engine.execution.ConditionEvaluator;
 import org.junit.jupiter.engine.execution.JupiterEngineExecutionContext;
 import org.junit.jupiter.engine.extension.ExtensionRegistry;
-import org.junit.platform.commons.JUnitException;
 import org.junit.platform.commons.util.ExceptionUtils;
 import org.junit.platform.commons.util.UnrecoverableExceptions;
 import org.junit.platform.engine.DiscoveryIssue;
@@ -139,8 +138,7 @@ public ExecutionMode getExecutionMode() {
 			return executionMode.get();
 		}
 		Optional<TestDescriptor> parent = getParent();
-		while (parent.isPresent() && parent.get() instanceof JupiterTestDescriptor) {
-			JupiterTestDescriptor jupiterParent = (JupiterTestDescriptor) parent.get();
+		while (parent.isPresent() && parent.get() instanceof JupiterTestDescriptor jupiterParent) {
 			executionMode = jupiterParent.getExplicitExecutionMode();
 			if (executionMode.isPresent()) {
 				return executionMode.get();
@@ -171,13 +169,10 @@ Optional<ExecutionMode> getExecutionModeFromAnnotation(AnnotatedElement element)
 	}
 
 	public static ExecutionMode toExecutionMode(org.junit.jupiter.api.parallel.ExecutionMode mode) {
-		switch (mode) {
-			case CONCURRENT:
-				return ExecutionMode.CONCURRENT;
-			case SAME_THREAD:
-				return ExecutionMode.SAME_THREAD;
-		}
-		throw new JUnitException("Unknown ExecutionMode: " + mode);
+		return switch (mode) {
+			case CONCURRENT -> ExecutionMode.CONCURRENT;
+			case SAME_THREAD -> ExecutionMode.SAME_THREAD;
+		};
 	}
 
 	@Override

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/LifecycleMethodUtils.java

@@ -13,7 +13,6 @@
 import static org.junit.jupiter.engine.support.MethodReflectionUtils.getReturnType;
 import static org.junit.platform.commons.support.AnnotationSupport.findAnnotatedMethods;
 import static org.junit.platform.commons.support.AnnotationSupport.findAnnotation;
-import static org.junit.platform.commons.util.CollectionUtils.toUnmodifiableList;
 import static org.junit.platform.engine.support.discovery.DiscoveryIssueReporter.Condition.alwaysSatisfied;
 
 import java.lang.annotation.Annotation;
@@ -134,7 +133,7 @@ private static List<Method> findMethodsAndCheckVoidReturnType(Class<?> testClass
 				.peek(isNotPrivateWarning(issueReporter, annotationType::getSimpleName).toConsumer()) //
 				.filter(returnsPrimitiveVoid(issueReporter, __ -> annotationType.getSimpleName()).and(
 					additionalCondition).toPredicate()) //
-				.collect(toUnmodifiableList());
+				.toList();
 	}
 
 	private static Condition<Method> isStatic(DiscoveryIssueReporter issueReporter,