diff --git a/buildSrc/build.gradle b/buildSrc/build.gradle
index 6176fc8b5c1..b7beebd58ed 100644
--- a/buildSrc/build.gradle
+++ b/buildSrc/build.gradle
@@ -10,8 +10,8 @@ repositories {
 	maven { url "https://repo.spring.io/release" }
 }
 
-sourceCompatibility = 1.8
-targetCompatibility = 1.8
+sourceCompatibility = 17
+targetCompatibility = 17
 
 dependencies {
 	checkstyle "io.spring.javaformat:spring-javaformat-checkstyle:${javaFormatVersion}"
@@ -22,8 +22,8 @@ dependencies {
 	implementation("org.gradle:test-retry-gradle-plugin:1.1.9")
 	implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.0")
 	implementation("org.jetbrains.kotlin:kotlin-compiler-embeddable:1.5.0")
-	implementation("org.springframework:spring-core:5.2.2.RELEASE")
-	implementation("org.springframework:spring-web:5.2.2.RELEASE")
+	implementation("org.springframework:spring-core:5.3.10")
+	implementation("org.springframework:spring-web:5.3.10")
 	implementation("io.spring.javaformat:spring-javaformat-gradle-plugin:${javaFormatVersion}")
 	testImplementation("org.assertj:assertj-core:3.11.1")
 	testImplementation("org.apache.logging.log4j:log4j-core:2.12.1")
diff --git a/buildSrc/src/main/java/org/springframework/boot/build/JavaConventions.java b/buildSrc/src/main/java/org/springframework/boot/build/JavaConventions.java
index d82ba98cec5..1d4614033b9 100644
--- a/buildSrc/src/main/java/org/springframework/boot/build/JavaConventions.java
+++ b/buildSrc/src/main/java/org/springframework/boot/build/JavaConventions.java
@@ -45,6 +45,7 @@ import org.gradle.api.tasks.bundling.Jar;
 import org.gradle.api.tasks.compile.JavaCompile;
 import org.gradle.api.tasks.javadoc.Javadoc;
 import org.gradle.api.tasks.testing.Test;
+import org.gradle.external.javadoc.CoreJavadocOptions;
 import org.gradle.testretry.TestRetryPlugin;
 import org.gradle.testretry.TestRetryTaskExtension;
 
@@ -59,7 +60,7 @@ import org.springframework.util.StringUtils;
  * plugin is applied:
  *
  * <ul>
- * <li>The project is configured with source and target compatibility of 1.8
+ * <li>The project is configured with source and target compatibility of 17
  * <li>{@link SpringJavaFormatPlugin Spring Java Format}, {@link CheckstylePlugin
  * Checkstyle}, {@link TestFailuresPlugin Test Failures}, and {@link TestRetryPlugin Test
  * Retry} plugins are applied
@@ -74,9 +75,9 @@ import org.springframework.util.StringUtils;
  * {@link JavaPlugin} applied
  * <li>{@link JavaCompile}, {@link Javadoc}, and {@link Format} tasks are configured to
  * use UTF-8 encoding
- * <li>{@link JavaCompile} tasks are configured to use {@code -parameters}.
- * <li>When building with Java 8, {@link JavaCompile} tasks are also configured to:
+ * <li>{@link JavaCompile} tasks are configured to:
  * <ul>
+ * <li>Use {@code -parameters}.
  * <li>Treat warnings as errors
  * <li>Enable {@code unchecked}, {@code deprecation}, {@code rawtypes}, and {@code varags}
  * warnings
@@ -102,7 +103,7 @@ import org.springframework.util.StringUtils;
  */
 class JavaConventions {
 
-	private static final String SOURCE_AND_TARGET_COMPATIBILITY = "1.8";
+	private static final String SOURCE_AND_TARGET_COMPATIBILITY = "17";
 
 	void apply(Project project) {
 		project.getPlugins().withType(JavaBasePlugin.class, (java) -> {
@@ -178,7 +179,12 @@ class JavaConventions {
 	}
 
 	private void configureJavadocConventions(Project project) {
-		project.getTasks().withType(Javadoc.class, (javadoc) -> javadoc.getOptions().source("1.8").encoding("UTF-8"));
+		project.getTasks().withType(Javadoc.class, (javadoc) -> {
+			CoreJavadocOptions options = (CoreJavadocOptions) javadoc.getOptions();
+			options.source("17");
+			options.encoding("UTF-8");
+			options.addStringOption("Xdoclint:none", "-quiet");
+		});
 	}
 
 	private void configureJavaConventions(Project project) {
@@ -196,17 +202,11 @@ class JavaConventions {
 				compile.setSourceCompatibility(SOURCE_AND_TARGET_COMPATIBILITY);
 				compile.setTargetCompatibility(SOURCE_AND_TARGET_COMPATIBILITY);
 			}
-			else if (buildingWithJava8(project)) {
-				args.addAll(Arrays.asList("-Werror", "-Xlint:unchecked", "-Xlint:deprecation", "-Xlint:rawtypes",
-						"-Xlint:varargs"));
-			}
+			args.addAll(Arrays.asList("-Werror", "-Xlint:unchecked", "-Xlint:deprecation", "-Xlint:rawtypes",
+					"-Xlint:varargs"));
 		});
 	}
 
-	private boolean buildingWithJava8(Project project) {
-		return !project.hasProperty("toolchainVersion") && JavaVersion.current() == JavaVersion.VERSION_1_8;
-	}
-
 	private void configureSpringJavaFormat(Project project) {
 		project.getPlugins().apply(SpringJavaFormatPlugin.class);
 		project.getTasks().withType(Format.class, (Format) -> Format.setEncoding("UTF-8"));
diff --git a/buildSrc/src/main/java/org/springframework/boot/build/mavenplugin/MavenPluginPlugin.java b/buildSrc/src/main/java/org/springframework/boot/build/mavenplugin/MavenPluginPlugin.java
index 79e1b197de6..aa3b2a8ff97 100644
--- a/buildSrc/src/main/java/org/springframework/boot/build/mavenplugin/MavenPluginPlugin.java
+++ b/buildSrc/src/main/java/org/springframework/boot/build/mavenplugin/MavenPluginPlugin.java
@@ -144,7 +144,7 @@ public class MavenPluginPlugin implements Plugin<Project> {
 	private MavenExec createGenerateHelpMojoTask(Project project, File helpMojoDir) {
 		MavenExec task = project.getTasks().create("generateHelpMojo", MavenExec.class);
 		task.setProjectDir(helpMojoDir);
-		task.args("org.apache.maven.plugins:maven-plugin-plugin:3.6.0:helpmojo");
+		task.args("org.apache.maven.plugins:maven-plugin-plugin:3.6.1:helpmojo");
 		task.getOutputs().dir(new File(helpMojoDir, "target/generated-sources/plugin"));
 		return task;
 	}
@@ -211,7 +211,7 @@ public class MavenPluginPlugin implements Plugin<Project> {
 
 	private MavenExec createGeneratePluginDescriptorTask(Project project, File mavenDir) {
 		MavenExec generatePluginDescriptor = project.getTasks().create("generatePluginDescriptor", MavenExec.class);
-		generatePluginDescriptor.args("org.apache.maven.plugins:maven-plugin-plugin:3.6.0:descriptor");
+		generatePluginDescriptor.args("org.apache.maven.plugins:maven-plugin-plugin:3.6.1:descriptor");
 		generatePluginDescriptor.getOutputs().dir(new File(mavenDir, "target/classes/META-INF/maven"));
 		generatePluginDescriptor.getInputs().dir(new File(mavenDir, "target/classes/org"))
 				.withPathSensitivity(PathSensitivity.RELATIVE).withPropertyName("plugin classes");
diff --git a/buildSrc/src/test/java/org/springframework/boot/build/ConventionsPluginTests.java b/buildSrc/src/test/java/org/springframework/boot/build/ConventionsPluginTests.java
index 81b896bea9e..eb4127fdf1d 100644
--- a/buildSrc/src/test/java/org/springframework/boot/build/ConventionsPluginTests.java
+++ b/buildSrc/src/test/java/org/springframework/boot/build/ConventionsPluginTests.java
@@ -73,7 +73,7 @@ class ConventionsPluginTests {
 			out.println("    id 'org.springframework.boot.conventions'");
 			out.println("}");
 			out.println("version = '1.2.3'");
-			out.println("sourceCompatibility = '1.8'");
+			out.println("sourceCompatibility = '17'");
 			out.println("description 'Test project for manifest customization'");
 			out.println("jar.archiveFileName = 'test.jar'");
 		}
@@ -90,7 +90,7 @@ class ConventionsPluginTests {
 					.isEqualTo(this.projectDir.getName().replace("-", "."));
 			assertThat(mainAttributes.getValue("Implementation-Version")).isEqualTo("1.2.3");
 			assertThat(mainAttributes.getValue("Built-By")).isEqualTo("Spring");
-			assertThat(mainAttributes.getValue("Build-Jdk-Spec")).isEqualTo("1.8");
+			assertThat(mainAttributes.getValue("Build-Jdk-Spec")).isEqualTo("17");
 		}
 	}
 
@@ -103,7 +103,7 @@ class ConventionsPluginTests {
 			out.println("    id 'org.springframework.boot.conventions'");
 			out.println("}");
 			out.println("version = '1.2.3'");
-			out.println("sourceCompatibility = '1.8'");
+			out.println("sourceCompatibility = '17'");
 			out.println("description 'Test'");
 			out.println("repositories {");
 			out.println("    mavenCentral()");
@@ -125,7 +125,7 @@ class ConventionsPluginTests {
 					.isEqualTo(this.projectDir.getName().replace("-", "."));
 			assertThat(mainAttributes.getValue("Implementation-Version")).isEqualTo("1.2.3");
 			assertThat(mainAttributes.getValue("Built-By")).isEqualTo("Spring");
-			assertThat(mainAttributes.getValue("Build-Jdk-Spec")).isEqualTo("1.8");
+			assertThat(mainAttributes.getValue("Build-Jdk-Spec")).isEqualTo("17");
 		}
 	}
 
@@ -138,7 +138,7 @@ class ConventionsPluginTests {
 			out.println("    id 'org.springframework.boot.conventions'");
 			out.println("}");
 			out.println("version = '1.2.3'");
-			out.println("sourceCompatibility = '1.8'");
+			out.println("sourceCompatibility = '17'");
 			out.println("description 'Test'");
 			out.println("repositories {");
 			out.println("    mavenCentral()");
@@ -160,7 +160,7 @@ class ConventionsPluginTests {
 					.isEqualTo(this.projectDir.getName().replace("-", "."));
 			assertThat(mainAttributes.getValue("Implementation-Version")).isEqualTo("1.2.3");
 			assertThat(mainAttributes.getValue("Built-By")).isEqualTo("Spring");
-			assertThat(mainAttributes.getValue("Build-Jdk-Spec")).isEqualTo("1.8");
+			assertThat(mainAttributes.getValue("Build-Jdk-Spec")).isEqualTo("17");
 		}
 	}
 
diff --git a/ci/images/ci-image-jdk11/Dockerfile b/ci/images/ci-image-jdk11/Dockerfile
deleted file mode 100644
index 75c043fbfae..00000000000
--- a/ci/images/ci-image-jdk11/Dockerfile
+++ /dev/null
@@ -1,12 +0,0 @@
-FROM ubuntu:focal-20211006
-
-ADD setup.sh /setup.sh
-ADD get-jdk-url.sh /get-jdk-url.sh
-ADD get-docker-url.sh /get-docker-url.sh
-RUN ./setup.sh java11
-
-ENV JAVA_HOME /opt/openjdk
-ENV PATH $JAVA_HOME/bin:$PATH
-ADD docker-lib.sh /docker-lib.sh
-
-ENTRYPOINT [ "switch", "shell=/bin/bash", "--", "codep", "/bin/docker daemon" ]
diff --git a/ci/images/ci-image-jdk17/Dockerfile b/ci/images/ci-image-jdk17/Dockerfile
deleted file mode 100644
index a23e34aed08..00000000000
--- a/ci/images/ci-image-jdk17/Dockerfile
+++ /dev/null
@@ -1,12 +0,0 @@
-FROM ubuntu:focal-20211006
-
-ADD setup.sh /setup.sh
-ADD get-jdk-url.sh /get-jdk-url.sh
-ADD get-docker-url.sh /get-docker-url.sh
-RUN ./setup.sh java8 java17
-
-ENV JAVA_HOME /opt/openjdk
-ENV PATH $JAVA_HOME/bin:$PATH
-ADD docker-lib.sh /docker-lib.sh
-
-ENTRYPOINT [ "switch", "shell=/bin/bash", "--", "codep", "/bin/docker daemon" ]
diff --git a/ci/images/ci-image/Dockerfile b/ci/images/ci-image/Dockerfile
index 36c2ba862b4..32e9f076066 100644
--- a/ci/images/ci-image/Dockerfile
+++ b/ci/images/ci-image/Dockerfile
@@ -3,7 +3,7 @@ FROM ubuntu:focal-20211006
 ADD setup.sh /setup.sh
 ADD get-jdk-url.sh /get-jdk-url.sh
 ADD get-docker-url.sh /get-docker-url.sh
-RUN ./setup.sh java8
+RUN ./setup.sh java17
 
 ENV JAVA_HOME /opt/openjdk
 ENV PATH $JAVA_HOME/bin:$PATH
diff --git a/ci/images/get-jdk-url.sh b/ci/images/get-jdk-url.sh
index f20501cad68..0c020e7b6ae 100755
--- a/ci/images/get-jdk-url.sh
+++ b/ci/images/get-jdk-url.sh
@@ -2,12 +2,6 @@
 set -e
 
 case "$1" in
-	java8)
-		 echo "https://github.com/adoptium/temurin8-binaries/releases/download/jdk8u312-b07/OpenJDK8U-jdk_x64_linux_hotspot_8u312b07.tar.gz"
-	;;
-	java11)
-		 echo "https://github.com/adoptium/temurin11-binaries/releases/download/jdk-11.0.13%2B8/OpenJDK11U-jdk_x64_linux_hotspot_11.0.13_8.tar.gz"
-	;;
 	java17)
 		 echo "https://github.com/adoptium/temurin17-binaries/releases/download/jdk-17.0.1%2B12/OpenJDK17U-jdk_x64_linux_hotspot_17.0.1_12.tar.gz"
 	;;
diff --git a/ci/pipeline.yml b/ci/pipeline.yml
index 42558839e98..998dcb9665b 100644
--- a/ci/pipeline.yml
+++ b/ci/pipeline.yml
@@ -171,18 +171,6 @@ resources:
   source:
     <<: *registry-image-resource-source
     repository: ((docker-hub-organization))/spring-boot-ci
-- name: ci-image-jdk11
-  type: registry-image
-  icon: docker
-  source:
-    <<: *registry-image-resource-source
-    repository: ((docker-hub-organization))/spring-boot-ci-jdk11
-- name: ci-image-jdk17
-  type: registry-image
-  icon: docker
-  source:
-    <<: *registry-image-resource-source
-    repository: ((docker-hub-organization))/spring-boot-ci-jdk17
 - name: paketo-builder-base-image
   type: registry-image
   icon: docker
@@ -205,22 +193,6 @@ resources:
     access_token: ((github-ci-status-token))
     branch: ((branch))
     context: build
-- name: repo-status-jdk11-build
-  type: github-status-resource
-  icon: eye-check-outline
-  source:
-    repository: ((github-repo-name))
-    access_token: ((github-ci-status-token))
-    branch: ((branch))
-    context: jdk11-build
-- name: repo-status-jdk17-build
-  type: github-status-resource
-  icon: eye-check-outline
-  source:
-    repository: ((github-repo-name))
-    access_token: ((github-ci-status-token))
-    branch: ((branch))
-    context: jdk17-build
 - name: slack-alert
   type: slack-notification
   icon: slack
@@ -248,66 +220,29 @@ jobs:
   - get: ci-images-git-repo
     trigger: true
   - get: git-repo
-  - in_parallel:
-    - task: build-ci-image
-      privileged: true
-      file: git-repo/ci/tasks/build-ci-image.yml
-      output_mapping:
-        image: ci-image
-      vars:
-        ci-image-name: ci-image
-        <<: *docker-hub-mirror-vars
-    - task: build-ci-image-jdk11
-      privileged: true
-      file: git-repo/ci/tasks/build-ci-image.yml
-      output_mapping:
-        image: ci-image-jdk11
-      vars:
-        ci-image-name: ci-image-jdk11
-        <<: *docker-hub-mirror-vars
-    - task: build-ci-image-jdk17
-      privileged: true
-      file: git-repo/ci/tasks/build-ci-image.yml
-      output_mapping:
-        image: ci-image-jdk17
-      vars:
-        ci-image-name: ci-image-jdk17
-        <<: *docker-hub-mirror-vars
-  - in_parallel:
-    - put: ci-image
-      params:
-        image: ci-image/image.tar
-    - put: ci-image-jdk11
-      params:
-        image: ci-image-jdk11/image.tar
-    - put: ci-image-jdk17
-      params:
-        image: ci-image-jdk17/image.tar
+  - task: build-ci-image
+    privileged: true
+    file: git-repo/ci/tasks/build-ci-image.yml
+    output_mapping:
+      image: ci-image
+    vars:
+      ci-image-name: ci-image
+      <<: *docker-hub-mirror-vars
+  - put: ci-image
+    params:
+      image: ci-image/image.tar
 - name: detect-jdk-updates
   plan:
   - get: git-repo
   - get: every-wednesday
     trigger: true
   - get: ci-image
-  - in_parallel:
-    - task: detect-jdk8-update
-      image: ci-image
-      file: git-repo/ci/tasks/detect-jdk-updates.yml
-      params:
-        <<: *github-task-params
-        JDK_VERSION: java8
-    - task: detect-jdk11-update
-      image: ci-image
-      file: git-repo/ci/tasks/detect-jdk-updates.yml
-      params:
-        <<: *github-task-params
-        JDK_VERSION: java11
-    - task: detect-jdk17-update
-      image: ci-image
-      file: git-repo/ci/tasks/detect-jdk-updates.yml
-      params:
-        <<: *github-task-params
-        JDK_VERSION: java17
+  - task: detect-jdk17-update
+    image: ci-image
+    file: git-repo/ci/tasks/detect-jdk-updates.yml
+    params:
+      <<: *github-task-params
+      JDK_VERSION: java17
 - name: detect-ubuntu-image-updates
   plan:
   - get: git-repo
@@ -395,63 +330,6 @@ jobs:
       params:
         path: git-repo
         status: failure
-- name: jdk11-build
-  serial: true
-  public: true
-  plan:
-  - get: ci-image-jdk11
-  - get: git-repo
-    trigger: true
-  - put: repo-status-jdk11-build
-    params: { state: "pending", commit: "git-repo" }
-  - do:
-    - task: build-project
-      image: ci-image-jdk11
-      <<: *build-project-task-params
-    on_failure:
-      do:
-      - put: repo-status-jdk11-build
-        params: { state: "failure", commit: "git-repo" }
-      - put: slack-alert
-        params:
-          <<: *slack-fail-params
-  - put: repo-status-jdk11-build
-    params: { state: "success", commit: "git-repo" }
-  - put: slack-alert
-    params:
-      <<: *slack-success-params
-- name: jdk17-build
-  serial: true
-  public: true
-  plan:
-    - get: ci-image-jdk17
-    - get: git-repo
-      trigger: true
-    - put: repo-status-jdk17-build
-      params: { state: "pending", commit: "git-repo" }
-    - do:
-        - task: build-project
-          image: ci-image-jdk17
-          privileged: true
-          timeout: ((task-timeout))
-          file: git-repo/ci/tasks/build-project.yml
-          params:
-            BRANCH: ((branch))
-            TOOLCHAIN_JAVA_VERSION: 17
-            <<: *gradle-enterprise-task-params
-            <<: *docker-hub-task-params
-      on_failure:
-        do:
-          - put: repo-status-jdk17-build
-            params: { state: "failure", commit: "git-repo" }
-          - put: slack-alert
-            params:
-              <<: *slack-fail-params
-    - put: repo-status-jdk17-build
-      params: { state: "success", commit: "git-repo" }
-    - put: slack-alert
-      params:
-        <<: *slack-success-params
 - name: windows-build
   serial: true
   plan:
@@ -725,64 +603,13 @@ jobs:
     - put: slack-alert
       params:
         <<: *slack-success-params
-- name: jdk11-run-system-tests
-  serial: true
-  public: true
-  plan:
-    - get: ci-image-jdk11
-    - get: git-repo
-    - get: paketo-builder-base-image
-      trigger: true
-    - get: daily
-      trigger: true
-    - do:
-        - task: run-system-tests
-          image: ci-image-jdk11
-          <<: *run-system-tests-task-params
-      on_failure:
-        do:
-          - put: slack-alert
-            params:
-              <<: *slack-fail-params
-    - put: slack-alert
-      params:
-        <<: *slack-success-params
-- name: jdk17-run-system-tests
-  serial: true
-  public: true
-  plan:
-    - get: ci-image-jdk17
-    - get: git-repo
-    - get: paketo-builder-base-image
-      trigger: true
-    - get: daily
-      trigger: true
-    - do:
-        - task: run-system-tests
-          image: ci-image-jdk17
-          privileged: true
-          timeout: ((task-timeout))
-          file: git-repo/ci/tasks/run-system-tests.yml
-          params:
-            BRANCH: ((branch))
-            TOOLCHAIN_JAVA_VERSION: 17
-            <<: *gradle-enterprise-task-params
-            <<: *docker-hub-task-params
-      on_failure:
-        do:
-          - put: slack-alert
-            params:
-              <<: *slack-fail-params
-    - put: slack-alert
-      params:
-        <<: *slack-success-params
 groups:
 - name: "builds"
-  jobs: ["build", "jdk11-build", "jdk17-build", "windows-build"]
+  jobs: ["build", "windows-build"]
 - name: "releases"
   jobs: ["stage-milestone", "stage-rc", "stage-release", "promote-milestone", "promote-rc", "promote-release", "create-github-release", "publish-gradle-plugin", "publish-to-sdkman", "update-homebrew-tap"]
 - name: "system-tests"
-  jobs: ["run-system-tests", "jdk11-run-system-tests", "jdk17-run-system-tests"]
+  jobs: ["run-system-tests"]
 - name: "ci-images"
   jobs: ["build-ci-images", "detect-docker-updates", "detect-jdk-updates", "detect-ubuntu-image-updates"]
 - name: "pull-requests"
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/LaunchedURLClassLoader.java b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/LaunchedURLClassLoader.java
index c90d8c3fc64..6089a76b457 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/LaunchedURLClassLoader.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/LaunchedURLClassLoader.java
@@ -139,10 +139,10 @@ public class LaunchedURLClassLoader extends URLClassLoader {
 			}
 			catch (IllegalArgumentException ex) {
 				// Tolerate race condition due to being parallel capable
-				if (getPackage(name) == null) {
+				if (getDefinedPackage(name) == null) {
 					// This should never happen as the IllegalArgumentException indicates
 					// that the package has already been defined and, therefore,
-					// getPackage(name) should not return null.
+					// getDefinedPackage(name) should not return null.
 					throw new AssertionError("Package " + name + " has already been defined but it could not be found");
 				}
 			}
@@ -192,16 +192,17 @@ public class LaunchedURLClassLoader extends URLClassLoader {
 		int lastDot = className.lastIndexOf('.');
 		if (lastDot >= 0) {
 			String packageName = className.substring(0, lastDot);
-			if (getPackage(packageName) == null) {
+			if (getDefinedPackage(packageName) == null) {
 				try {
 					definePackage(className, packageName);
 				}
 				catch (IllegalArgumentException ex) {
 					// Tolerate race condition due to being parallel capable
-					if (getPackage(packageName) == null) {
+					if (getDefinedPackage(packageName) == null) {
 						// This should never happen as the IllegalArgumentException
 						// indicates that the package has already been defined and,
-						// therefore, getPackage(name) should not have returned null.
+						// therefore, getDefinedPackage(name) should not have returned
+						// null.
 						throw new AssertionError(
 								"Package " + packageName + " has already been defined but it could not be found");
 					}
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/AbstractRunMojo.java b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/AbstractRunMojo.java
index 83ec65ed16d..a23bb5860cf 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/AbstractRunMojo.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/AbstractRunMojo.java
@@ -557,7 +557,7 @@ public abstract class AbstractRunMojo extends AbstractDependencyFilterMojo {
 			try {
 				Class<?> startClass = Class.forName(this.startClassName, false, classLoader);
 				Method mainMethod = startClass.getMethod("main", String[].class);
-				if (!mainMethod.isAccessible()) {
+				if (!mainMethod.canAccess(null)) {
 					mainMethod.setAccessible(true);
 				}
 				mainMethod.invoke(null, new Object[] { this.args });
diff --git a/spring-boot-project/spring-boot/build.gradle b/spring-boot-project/spring-boot/build.gradle
index 246b24ae2f0..05dcde61228 100644
--- a/spring-boot-project/spring-boot/build.gradle
+++ b/spring-boot-project/spring-boot/build.gradle
@@ -177,6 +177,6 @@ compileJava {
 	doLast new org.springframework.boot.build.log4j2.ReproducibleLog4j2PluginsDatAction()
 }
 
-toolchain {
-	testJvmArgs.add("--add-opens=java.base/java.net=ALL-UNNAMED")
+test {
+	jvmArgs += "--add-opens=java.base/java.net=ALL-UNNAMED"
 }
diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/BeanDefinitionLoader.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/BeanDefinitionLoader.java
index b59ec87f849..c8f136c433e 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/BeanDefinitionLoader.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/BeanDefinitionLoader.java
@@ -256,7 +256,7 @@ class BeanDefinitionLoader {
 			String path = ((ClassPathResource) resource).getPath();
 			if (path.indexOf('.') == -1) {
 				try {
-					return Package.getPackage(path) == null;
+					return getClass().getClassLoader().getDefinedPackage(path) == null;
 				}
 				catch (Exception ex) {
 					// Ignore
@@ -267,7 +267,7 @@ class BeanDefinitionLoader {
 	}
 
 	private Package findPackage(CharSequence source) {
-		Package pkg = Package.getPackage(source.toString());
+		Package pkg = getClass().getClassLoader().getDefinedPackage(source.toString());
 		if (pkg != null) {
 			return pkg;
 		}
@@ -285,7 +285,7 @@ class BeanDefinitionLoader {
 		catch (Exception ex) {
 			// swallow exception and continue
 		}
-		return Package.getPackage(source.toString());
+		return getClass().getClassLoader().getDefinedPackage(source.toString());
 	}
 
 	/**
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/reactor/DebugAgentEnvironmentPostProcessorTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/reactor/DebugAgentEnvironmentPostProcessorTests.java
index 034d7632f14..ac965f17a87 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/reactor/DebugAgentEnvironmentPostProcessorTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/reactor/DebugAgentEnvironmentPostProcessorTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
 
 package org.springframework.boot.reactor;
 
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import reactor.core.Scannable;
 import reactor.core.publisher.Flux;
@@ -30,7 +31,8 @@ import static org.assertj.core.api.Assertions.assertThat;
  *
  * @author Brian Clozel
  */
-@ClassPathOverrides("io.projectreactor:reactor-tools:3.3.0.RELEASE")
+@Disabled("We need the not-yet-released reactor-tools 3.4.11 for JDK 17 compatibility")
+@ClassPathOverrides("io.projectreactor:reactor-tools:3.4.11")
 class DebugAgentEnvironmentPostProcessorTests {
 
 	static {
diff --git a/spring-boot-tests/spring-boot-integration-tests/spring-boot-loader-tests/src/intTest/java/org/springframework/boot/loader/LoaderIntegrationTests.java b/spring-boot-tests/spring-boot-integration-tests/spring-boot-loader-tests/src/intTest/java/org/springframework/boot/loader/LoaderIntegrationTests.java
index 1abe0c519cf..fdcf9d13410 100644
--- a/spring-boot-tests/spring-boot-integration-tests/spring-boot-loader-tests/src/intTest/java/org/springframework/boot/loader/LoaderIntegrationTests.java
+++ b/spring-boot-tests/spring-boot-integration-tests/spring-boot-loader-tests/src/intTest/java/org/springframework/boot/loader/LoaderIntegrationTests.java
@@ -40,7 +40,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 @Testcontainers(disabledWithoutDocker = true)
 class LoaderIntegrationTests {
 
-	private static final DockerImageName JRE = DockerImageName.parse("adoptopenjdk:15-jre-hotspot");
+	private static final DockerImageName JRE = DockerImageName.parse("eclipse-temurin:17.0.1_12-jdk-alpine");
 
 	private static ToStringConsumer output = new ToStringConsumer();