Support Gradle 7 and raise minimum supported version to 6.8

Closes gh-26026

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/asciidoc/index.adoc

@@ -42,8 +42,7 @@ Andy Wilkinson, Scott Frederick
 == Introduction
 The Spring Boot Gradle Plugin provides Spring Boot support in https://gradle.org[Gradle].
 It allows you to package executable jar or war archives, run Spring Boot applications, and use the dependency management provided by `spring-boot-dependencies`.
-Spring Boot's Gradle plugin requires Gradle 6 (6.3 or later).
-Gradle's {gradle-userguide}/configuration_cache.html[configuration cache] is supported when using Gradle 6.7 or later.
+Spring Boot's Gradle plugin requires Gradle 6.8 or 7.x and can be used with Gradle's {gradle-userguide}/configuration_cache.html[configuration cache].
 
 In addition to this user guide, {api-documentation}[API documentation] is also available.
 

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/asciidoc/managing-dependencies.adoc

@@ -1,6 +1,6 @@
 [[managing-dependencies]]
 == Managing Dependencies
-To manage dependencies in your Spring Boot application, you can either apply the {dependency-management-plugin}[`io.spring.dependency-management`] plugin or, if you are using Gradle 6 or later, use Gradle's native bom support.
+To manage dependencies in your Spring Boot application, you can either apply the {dependency-management-plugin}[`io.spring.dependency-management`] plugin or use Gradle's native bom support.
 The primary benefit of the former is that it offers property-based customization of managed versions, while using the latter will likely result in faster builds.
 
 

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/SpringBootPlugin.java

@@ -95,9 +95,9 @@ public class SpringBootPlugin implements Plugin<Project> {
 
 	private void verifyGradleVersion() {
 		GradleVersion currentVersion = GradleVersion.current();
-		if (currentVersion.compareTo(GradleVersion.version("6.3")) < 0) {
-			throw new GradleException("Spring Boot plugin requires Gradle 6 (6.3 or later). "
-					+ "The current version is " + currentVersion);
+		if (currentVersion.compareTo(GradleVersion.version("6.8")) < 0) {
+			throw new GradleException(
+					"Spring Boot plugin requires Gradle 6.8.x or 7.x. " + "The current version is " + currentVersion);
 		}
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/junit/GradleCompatibilityExtension.java

@@ -51,7 +51,7 @@ final class GradleCompatibilityExtension implements TestTemplateInvocationContex
 			GRADLE_VERSIONS = Arrays.asList("7.0");
 		}
 		else {
-			GRADLE_VERSIONS = Arrays.asList("6.3", "6.4.1", "6.5.1", "6.6.1", "6.7.1", "current", "7.0");
+			GRADLE_VERSIONS = Arrays.asList("current", "7.0");
 		}
 	}
 
@@ -74,7 +74,7 @@ final class GradleCompatibilityExtension implements TestTemplateInvocationContex
 			List<TestTemplateInvocationContext> invocationContexts = new ArrayList<>();
 			invocationContexts.add(new GradleVersionTestTemplateInvocationContext(version, false));
 			boolean configurationCache = gradleCompatibility.configurationCache();
-			if (configurationCache && GradleVersion.version(version).compareTo(GradleVersion.version("6.7")) >= 0) {
+			if (configurationCache) {
 				invocationContexts.add(new GradleVersionTestTemplateInvocationContext(version, true));
 			}
 			return invocationContexts.stream();

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/plugin/SpringBootPluginIntegrationTests.java

@@ -40,15 +40,15 @@ class SpringBootPluginIntegrationTests {
 	@DisabledForJreRange(min = JRE.JAVA_14)
 	@Test
 	void failFastWithVersionOfGradle6LowerThanRequired() {
-		BuildResult result = this.gradleBuild.gradleVersion("6.2.2").buildAndFail();
+		BuildResult result = this.gradleBuild.gradleVersion("6.7.1").buildAndFail();
 		assertThat(result.getOutput())
-				.contains("Spring Boot plugin requires Gradle 6 (6.3 or later). The current version is Gradle 6.2.2");
+				.contains("Spring Boot plugin requires Gradle 6.8.x or 7.x. The current version is Gradle 6.7.1");
 	}
 
 	@DisabledForJreRange(min = JRE.JAVA_16)
 	@Test
 	void succeedWithVersionOfGradle6MatchingWithIsRequired() {
-		this.gradleBuild.gradleVersion("6.3").build();
+		this.gradleBuild.gradleVersion("6.8").build();
 	}
 
 }