Deprecate unsupported JRE enum constants and update related conditions

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

@@ -92,6 +92,10 @@ repository on GitHub.
   - `InvocationInterceptor.interceptDynamicTest(Invocation, ExtensionContext)` method
 * The deprecated `junit.jupiter.tempdir.scope` configuration parameter is no longer
   supported.
+* The `JRE` enum constants for `JAVA_8` to `JAVA_16` have been deprecated because they can
+  no longer be used at runtime since `JAVA_17` is the new baseline.
+* `@EnabledForJreRange` and `@DisabledForJreRange` now use `JAVA_17` as their default
+  `min` value.
 
 [[release-notes-6.0.0-M1-junit-jupiter-new-features-and-improvements]]
 ==== New Features and Improvements

documentation/src/test/java/example/ConditionalTestExecutionDemo.java

@@ -10,10 +10,11 @@
 
 package example;
 
-import static org.junit.jupiter.api.condition.JRE.JAVA_11;
 import static org.junit.jupiter.api.condition.JRE.JAVA_17;
+import static org.junit.jupiter.api.condition.JRE.JAVA_18;
+import static org.junit.jupiter.api.condition.JRE.JAVA_19;
 import static org.junit.jupiter.api.condition.JRE.JAVA_21;
-import static org.junit.jupiter.api.condition.JRE.JAVA_9;
+import static org.junit.jupiter.api.condition.JRE.JAVA_25;
 import static org.junit.jupiter.api.condition.OS.LINUX;
 import static org.junit.jupiter.api.condition.OS.MAC;
 import static org.junit.jupiter.api.condition.OS.WINDOWS;
@@ -113,44 +114,44 @@ void onJava17And21() {
 	}
 
 	@Test
-	@EnabledForJreRange(min = JAVA_9, max = JAVA_11)
-	void fromJava9To11() {
+	@EnabledForJreRange(min = JAVA_21, max = JAVA_25)
+	void fromJava21To25() {
 		// ...
 	}
 
 	@Test
-	@EnabledForJreRange(min = JAVA_9)
-	void onJava9AndHigher() {
+	@EnabledForJreRange(min = JAVA_21)
+	void onJava21ndHigher() {
 		// ...
 	}
 
 	@Test
-	@EnabledForJreRange(max = JAVA_11)
-	void fromJava8To11() {
+	@EnabledForJreRange(max = JAVA_18)
+	void fromJava17To18() {
 		// ...
 	}
 
 	@Test
-	@DisabledOnJre(JAVA_9)
-	void notOnJava9() {
+	@DisabledOnJre(JAVA_19)
+	void notOnJava19() {
 		// ...
 	}
 
 	@Test
-	@DisabledForJreRange(min = JAVA_9, max = JAVA_11)
-	void notFromJava9To11() {
+	@DisabledForJreRange(min = JAVA_17, max = JAVA_17)
+	void notFromJava17To19() {
 		// ...
 	}
 
 	@Test
-	@DisabledForJreRange(min = JAVA_9)
-	void notOnJava9AndHigher() {
+	@DisabledForJreRange(min = JAVA_19)
+	void notOnJava19AndHigher() {
 		// ...
 	}
 
 	@Test
-	@DisabledForJreRange(max = JAVA_11)
-	void notFromJava8To11() {
+	@DisabledForJreRange(max = JAVA_18)
+	void notFromJava17To18() {
 		// ...
 	}
 	// end::user_guide_jre[]

gradle/plugins/code-generator/src/main/kotlin/junitbuild/generator/GenerateJreRelatedSourceCode.kt

@@ -57,9 +57,13 @@ abstract class GenerateJreRelatedSourceCode : DefaultTask() {
                 mapper.registerModule(KotlinModule.Builder().build())
                 mapper.readValue(input, object : TypeReference<List<JRE>>() {})
             }
+            val minRuntimeVersion = 17
+            val supportedJres = jres.filter { it.version >= minRuntimeVersion }
             val params = mapOf(
-                "jres" to jres,
-                "jresSortedByStringValue" to jres.sortedBy { it.version.toString() },
+                "minRuntimeVersion" to minRuntimeVersion,
+                "allJres" to jres,
+                "supportedJres" to supportedJres,
+                "supportedJresSortedByStringValue" to supportedJres.sortedBy { it.version.toString() },
                 "licenseHeader" to licenseHeaderFile.asFile.get().readText()
             )
             templates.forEach {

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

@@ -26,6 +26,9 @@
  */
 abstract class AbstractJreRangeCondition<A extends Annotation> extends BooleanExecutionCondition<A> {
 
+	private static final JRE DEFAULT_MINIMUM_JRE = JRE.JAVA_17;
+	private static final JRE DEFAULT_MAXIMUM_JRE = JRE.OTHER;
+
 	private final String annotationName;
 
 	AbstractJreRangeCondition(Class<A> annotationType, Function<A, String> customDisabledReason) {
@@ -58,17 +61,17 @@ protected final boolean isCurrentVersionWithinRange(JRE minJre, JRE maxJre, int
 		// Now that we have checked the basic preconditions, we need to ensure that we are
 		// using valid JRE enum constants.
 		if (!minJreSet) {
-			minJre = JRE.JAVA_8;
+			minJre = DEFAULT_MINIMUM_JRE;
 		}
 		if (!maxJreSet) {
-			maxJre = JRE.OTHER;
+			maxJre = DEFAULT_MAXIMUM_JRE;
 		}
 
 		int min = (minVersionSet ? minVersion : minJre.version());
 		int max = (maxVersionSet ? maxVersion : maxJre.version());
 
 		// Finally, we need to validate the effective minimum and maximum values.
-		Preconditions.condition((min != JRE.MINIMUM_VERSION || max != Integer.MAX_VALUE),
+		Preconditions.condition((min != DEFAULT_MINIMUM_JRE.version() || max != DEFAULT_MAXIMUM_JRE.version()),
 			() -> "You must declare a non-default value for the minimum or maximum value in @" + this.annotationName);
 		Preconditions.condition(min <= max,
 			() -> String.format("@%s's minimum value [%d] must be less than or equal to its maximum value [%d]",

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

@@ -96,7 +96,7 @@
 	 * {@link #minVersion() minVersion} instead.
 	 *
 	 * <p>Defaults to {@link JRE#UNDEFINED UNDEFINED}, which will be interpreted
-	 * as {@link JRE#JAVA_8 JAVA_8} if the {@link #minVersion() minVersion} is
+	 * as {@link JRE#JAVA_17 JAVA_17} if the {@link #minVersion() minVersion} is
 	 * not set.
 	 *
 	 * @see JRE

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

@@ -96,7 +96,7 @@
 	 * {@link #minVersion() minVersion} instead.
 	 *
 	 * <p>Defaults to {@link JRE#UNDEFINED UNDEFINED}, which will be interpreted
-	 * as {@link JRE#JAVA_8 JAVA_8} if the {@link #minVersion() minVersion} is
+	 * as {@link JRE#JAVA_17 JAVA_17} if the {@link #minVersion() minVersion} is
 	 * not set.
 	 *
 	 * @see JRE

junit-jupiter-api/src/templates/resources/main/org/junit/jupiter/api/condition/JRE.java.jte

@@ -2,7 +2,8 @@
 @import gg.jte.support.ForSupport
 @import junitbuild.generator.model.JRE
 
-@param List<JRE> jres
+@param int minRuntimeVersion
+@param List<JRE> allJres
 @param String licenseHeader
 ${licenseHeader}
 package org.junit.jupiter.api.condition;
@@ -11,26 +12,17 @@ import static org.apiguardian.api.API.Status.DEPRECATED;
 import static org.apiguardian.api.API.Status.EXPERIMENTAL;
 import static org.apiguardian.api.API.Status.STABLE;
 
-import java.lang.reflect.Method;
-
 import org.apiguardian.api.API;
-import org.junit.platform.commons.logging.Logger;
-import org.junit.platform.commons.logging.LoggerFactory;
-import org.junit.platform.commons.support.ReflectionSupport;
-import org.junit.platform.commons.util.StringUtils;
 
 /**
  * Enumeration of Java Runtime Environment (JRE) versions.
  *
  * <p>If the current JRE version can be detected but is not one of the predefined
  * constants in this enum, {@link #OTHER} will be considered to be the
- * {@linkplain #isCurrentVersion current JRE version}. If the current JRE version
- * cannot be detected &mdash; for example, if the {@code java.version} JVM system
- * property is undefined &mdash; {@link #UNDEFINED} will be considered to be the
- * current JRE version.
+ * {@linkplain #isCurrentVersion current JRE version}.
  *
  * @since 5.1
-@for(JRE jre : jres)<%--
+@for(JRE jre : allJres)<%--
 --%> * @see #JAVA_${jre.getVersion()}
 @endfor<%--
 --%> * @see #OTHER
@@ -54,22 +46,30 @@ public enum JRE {
 	 */
 	@API(status = EXPERIMENTAL, since = "5.12")
 	UNDEFINED(-1),
-@for(var jre : jres)
+@for(var jre : allJres)
 	/**
 	 * Java ${jre.getVersion()}.
-	@if(jre.getSince() != null)<%--
+	@if(jre.getSince() != null || jre.getVersion() < minRuntimeVersion)<%--
 --%> *
-	 * @since ${jre.getSince()}
+	@endif<%--
+--%>@if(jre.getSince() != null)<%--
+--%> * @since ${jre.getSince()}
+	@endif<%--
+--%>@if(jre.getVersion() < minRuntimeVersion)<%--
+--%> * @deprecated No longer supported at runtime; please use {@link #JAVA_17} or later
 	@endif<%--
 --%> */
-	@if(jre.getSince() != null)<%--
+	@if(jre.getVersion() < minRuntimeVersion)<%--
+--%>@API(status = DEPRECATED, since = "6.0") //
+	@Deprecated(since = "6.0", forRemoval = true)
+	@elseif(jre.getSince() != null)<%--
 --%>@API(status = STABLE, since = "${jre.getSince()}")
 	@endif<%--
 --%>JAVA_${jre.getVersion()}(${jre.getVersion()}),
 @endfor
 	/**
 	 * A JRE version other than <%--
---%>@for(var jre : ForSupport.of(jres))<%--
+--%>@for(var jre : ForSupport.of(allJres))<%--
 	--%>@if(jre.isLast())or @endif<%--
 	--%>{@link #JAVA_${jre.get().getVersion()}}<%--
 	--%>@if(jre.isLast()).@else,@endif<%--
@@ -85,59 +85,13 @@ public enum JRE {
 
 	static final int UNDEFINED_VERSION = -1;
 
-	static final int MINIMUM_VERSION = 8;
-
-	private static final Logger logger = LoggerFactory.getLogger(JRE.class);
-
-	private static final int CURRENT_VERSION = determineCurrentVersion();
-
-	private static final JRE CURRENT_JRE = determineCurrentJre(CURRENT_VERSION);
-
-	private static int determineCurrentVersion() {
-		String javaVersion = System.getProperty("java.version");
-		boolean javaVersionIsBlank = StringUtils.isBlank(javaVersion);
+	static final int MINIMUM_VERSION = ${allJres.getFirst().getVersion()};
 
-		if (javaVersionIsBlank) {
-			logger.debug(
-				() -> "JVM system property 'java.version' is undefined. It is therefore not possible to detect Java 8.");
-		}
-
-		if (!javaVersionIsBlank && javaVersion.startsWith("1.8")) {
-			return 8;
-		}
-
-		try {
-			// java.lang.Runtime.version() is a static method available on Java 9+
-			// that returns an instance of java.lang.Runtime.Version which has the
-			// following method: public int major()
-			Method versionMethod = Runtime.class.getMethod("version");
-			Object version = ReflectionSupport.invokeMethod(versionMethod, null);
-			Method majorMethod = version.getClass().getMethod("major");
-			return (int) ReflectionSupport.invokeMethod(majorMethod, version);
-		}
-		catch (Exception ex) {
-			logger.debug(ex, () -> "Failed to determine the current JRE version via java.lang.Runtime.Version.");
-		}
-
-		return UNDEFINED_VERSION;
-	}
-
-	private static JRE determineCurrentJre(int currentVersion) {
-		switch (currentVersion) {
-			case UNDEFINED_VERSION:
-				return UNDEFINED;<%--
-			--%>@for(var jre : jres)
-			case ${jre.getVersion()}:
-				return JAVA_${jre.getVersion()};<%--
-			--%>@endfor
-			default:
-				return OTHER;
-		}
-	}
+	private static final int CURRENT_VERSION = Runtime.version().feature();
 
 	private final int version;
 
-	private JRE(int version) {
+	JRE(int version) {
 		this.version = version;
 	}
 
@@ -161,18 +115,18 @@ public enum JRE {
 	/**
 	 * @return {@code true} if <em>this</em> {@code JRE} is known to be the
 	 * Java Runtime Environment version for the currently executing JVM or if
-	 * the version is {@link #OTHER} or {@link #UNDEFINED}
+	 * the version is {@link #OTHER}
 	 *
 	 * @see #currentJre()
 	 * @see #currentVersionNumber()
 	 */
 	public boolean isCurrentVersion() {
-		return this == CURRENT_JRE;
+		return this == currentJre();
 	}
 
 	/**
 	 * @return the {@link JRE} for the currently executing JVM, potentially
-	 * {@link #OTHER} or {@link #UNDEFINED}
+	 * {@link #OTHER}
 	 *
 	 * @since 5.7
 	 * @see #currentVersionNumber()
@@ -186,14 +140,19 @@ public enum JRE {
 
 	/**
 	 * @return the {@link JRE} for the currently executing JVM, potentially
-	 * {@link #OTHER} or {@link #UNDEFINED}
+	 * {@link #OTHER}
 	 *
 	 * @since 5.12
 	 * @see #currentVersionNumber()
 	 */
 	@API(status = STABLE, since = "5.12")
 	public static JRE currentJre() {
-		return CURRENT_JRE;
+		return switch (CURRENT_VERSION) {<%--
+				--%>@for(var jre : allJres)
+			case ${jre.getVersion()} -> JAVA_${jre.getVersion()};<%--
+				--%>@endfor
+			default -> OTHER;
+		};
 	}
 
 	/**

junit-jupiter-api/src/templates/resources/testFixtures/org/junit/jupiter/api/condition/JavaVersionPredicates.java.jte

@@ -2,21 +2,21 @@
 @import gg.jte.support.ForSupport
 @import junitbuild.generator.model.JRE
 
-@param List<JRE> jres
+@param List<JRE> supportedJres
 @param String licenseHeader
 ${licenseHeader}
 package org.junit.jupiter.api.condition;
 
 public class JavaVersionPredicates {
 
 	private static final int JAVA_VERSION = Runtime.version().feature();
-@for(JRE jre : jres)
+@for(JRE jre : supportedJres)
 	static boolean onJava${jre.getVersion()}() {
 		return JAVA_VERSION == ${jre.getVersion()};
 	}
 @endfor
 	static boolean onKnownVersion() {
-		return @for(var jre : ForSupport.of(jres))onJava${jre.get().getVersion()}()@if(!jre.isLast()) //
+		return @for(var jre : ForSupport.of(supportedJres))onJava${jre.get().getVersion()}()@if(!jre.isLast()) //
 				|| @endif@endfor;
 	}
 }

jupiter-tests/src/templates/resources/test/org/junit/jupiter/api/condition/DisabledOnJreConditionTests.java.jte

@@ -1,14 +1,14 @@
 @import java.util.List
 @import junitbuild.generator.model.JRE
 
-@param List<JRE> jres
-@param List<JRE> jresSortedByStringValue
+@param List<JRE> supportedJres
+@param List<JRE> supportedJresSortedByStringValue
 @param String licenseHeader
 ${licenseHeader}
 package org.junit.jupiter.api.condition;
 
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-@for(var jre : jresSortedByStringValue)<%--
+@for(var jre : supportedJresSortedByStringValue)<%--
 --%>import static org.junit.jupiter.api.condition.JavaVersionPredicates.onJava${jre.getVersion()};
 @endfor<%--
 --%>import static org.junit.jupiter.api.condition.JavaVersionPredicates.onKnownVersion;
@@ -89,7 +89,7 @@ class DisabledOnJreConditionTests extends AbstractExecutionConditionTests {
 		assertDisabledOnCurrentJreIf(true);
 		assertCustomDisabledReasonIs("Disabled on every JRE");
 	}
-@for(var jre : jres)
+@for(var jre : supportedJres)
 	/**
 	 * @see DisabledOnJreIntegrationTests#jre${jre.getVersion()}()
 	 */
@@ -99,7 +99,7 @@ class DisabledOnJreConditionTests extends AbstractExecutionConditionTests {
 		assertDisabledOnCurrentJreIf(onJava${jre.getVersion()}());
 	}
 @endfor<%--
---%>@for(var jre : jres)
+--%>@for(var jre : supportedJres)
 	/**
 	 * @see DisabledOnJreIntegrationTests#version${jre.getVersion()}()
 	 */