Polish

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/invoker/cache/CachingOperationInvoker.java

@@ -182,25 +182,12 @@ public class CachingOperationInvoker implements OperationInvoker {
 			if (this == obj) {
 				return true;
 			}
-			if (obj == null) {
-				return false;
-			}
-			if (getClass() != obj.getClass()) {
+			if (obj == null || getClass() != obj.getClass()) {
 				return false;
 			}
 			CacheKey other = (CacheKey) obj;
-			if (this.apiVersion != other.apiVersion) {
-				return false;
-			}
-			if (this.principal == null) {
-				if (other.principal != null) {
-					return false;
-				}
-			}
-			else if (!this.principal.equals(other.principal)) {
-				return false;
-			}
-			return true;
+			return this.apiVersion.equals(other.apiVersion)
+					&& ObjectUtils.nullSafeEquals(this.principal, other.principal);
 		}
 
 		@Override
@@ -208,7 +195,7 @@ public class CachingOperationInvoker implements OperationInvoker {
 			final int prime = 31;
 			int result = 1;
 			result = prime * result + this.apiVersion.hashCode();
-			result = prime * result + ((this.principal == null) ? 0 : this.principal.hashCode());
+			result = prime * result + ObjectUtils.nullSafeHashCode(this.principal);
 			return result;
 		}
 

spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment.adoc

@@ -181,6 +181,8 @@ See the {spring-boot-module-api}/cloud/CloudFoundryVcapEnvironmentPostProcessor.
 
 TIP: The https://github.com/pivotal-cf/java-cfenv/[Java CFEnv] project is a better fit for tasks such as configuring a DataSource.
 
+
+
 [[cloud-deployment-kubernetes]]
 === Kubernetes
 Spring Boot auto-detects Kubernetes deployment environments by checking the environment for `"*_SERVICE_HOST"` and `"*_SERVICE_PORT"` variables.
@@ -188,6 +190,8 @@ You can override this detection with the configprop:management.health.probes.ena
 
 Spring Boot helps you to <<spring-boot-features.adoc#boot-features-application-availability-state,manage the state of your application>> and export it with <<production-ready-features.adoc#production-ready-kubernetes-probes, HTTP Kubernetes Probes using Actuator>>.
 
+
+
 [[cloud-deployment-kubernetes-container-lifecycle]]
 ==== Kubernetes Container Lifecycle
 When Kubernetes deletes an application instance, the shutdown process involves several subsystems concurrently: shutdown hooks, unregistering the service, removing the instance from the load-balancer...
@@ -207,6 +211,7 @@ lifecycle:
 Once the pre-stop hook has completed, SIGTERM will be sent to the container and <<spring-boot-features#boot-features-graceful-shutdown,graceful shutdown>> will begin, allowing any remaining in-flight requests to complete.
 
 
+
 [[cloud-deployment-heroku]]
 === Heroku
 Heroku is another popular PaaS platform.

spring-boot-project/spring-boot-docs/src/docs/asciidoc/production-ready-features.adoc

@@ -870,6 +870,7 @@ It's also possible to override the `show-details` and `roles` properties if requ
 TIP: You can use `@Qualifier("groupname")` if you need to register custom `StatusAggregator` or `HttpCodeStatusMapper` beans for use with the group.
 
 
+
 [[production-ready-kubernetes-probes]]
 === Kubernetes Probes
 Applications deployed on Kubernetes can provide information about their internal state with https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#container-probes[Container Probes].
@@ -905,6 +906,8 @@ The `"startupProbe"` is not necessarily needed here as the `"readinessProbe"` fa
 WARNING: If your Actuator endpoints are deployed on a separate management context, be aware that endpoints are then not using the same web infrastructure (port, connection pools, framework components) as the main application.
 In this case, a Probe check could be successful even if the main application does not work properly (for example, it cannot accept new connections).
 
+
+
 [[production-ready-kubernetes-probes-external-state]]
 ==== Checking external state with Kubernetes Probes
 Actuator configures the "liveness" and "readiness" Probes as Health Groups; this means that all the <<production-ready-health-groups, Health Groups features>> are available for them.
@@ -927,6 +930,7 @@ Some external systems might not be shared by application instances or not essent
 Also, Kubernetes will react differently to applications being taken out of the load-balancer, depending on its https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/[autoscaling configuration].
 
 
+
 [[production-ready-kubernetes-probes-lifecycle]]
 ==== Application lifecycle and Probes states
 An important aspect of the Kubernetes Probes support is its consistency with the application lifecycle.
@@ -952,7 +956,6 @@ When a Spring Boot application starts:
 |live
 |ready
 |Startup tasks are finished. The application is receiving traffic.
-
 |===
 
 When a Spring Boot application shuts down:
@@ -975,12 +978,12 @@ When a Spring Boot application shuts down:
 |broken
 |unready
 |The application context is closed and the application cannot serve traffic.
-
 |===
 
 TIP: Check out the <<deployment.adoc#cloud-deployment-kubernetes-container-lifecycle,Kubernetes container lifecycle section>> for more information about Kubernetes deployment.
 
 
+
 [[production-ready-application-info]]
 === Application Information
 Application information exposes various information collected from all {spring-boot-actuator-module-code}/info/InfoContributor.java[`InfoContributor`] beans defined in your `ApplicationContext`.

spring-boot-project/spring-boot-docs/src/docs/asciidoc/spring-boot-features.adoc

@@ -191,12 +191,15 @@ NOTE: There are some restrictions when creating an `ApplicationContext` hierarch
 For example, Web components *must* be contained within the child context, and the same `Environment` is used for both parent and child contexts.
 See the {spring-boot-module-api}/builder/SpringApplicationBuilder.html[`SpringApplicationBuilder` Javadoc] for full details.
 
+
+
 [[boot-features-application-availability-state]]
 === Application Availability State
 When deployed on plaftorms, applications can provide information about their availability to the platform using infrastructure like https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/[Kubernetes Probes].
 Spring Boot manages this application state with the `ApplicationAvailabilityProvider` and makes it available to application components and the platform itself.
 
 
+
 [[boot-features-application-availability-liveness]]
 ==== Liveness State
 The "Liveness" state of an application tells whether its internal state allows it to work correctly, or recover by itself if it's currently failing.
@@ -209,6 +212,8 @@ The internal state of Spring Boot applications is mostly represented by the Spri
 If the application context has started successfully, Spring Boot assumes that the application is in a valid state.
 An application is considered live as soon as the context has been refreshed, see <<boot-features-application-events-and-listeners, Spring Boot application lifecycle and related Application Events>>.
 
+
+
 [[boot-features-application-availability-readiness]]
 ==== Readiness State
 The "Readiness" state of an application tells whether the application is ready to handle traffic.

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/HttpClientHttp.java

@@ -150,8 +150,6 @@ class HttpClientHttp implements Http {
 
 	/**
 	 * {@link HttpEntity} to send {@link Content} content.
-	 *
-	 * @author Phillip Webb
 	 */
 	private static class WritableHttpEntity extends AbstractHttpEntity {
 

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

@@ -306,6 +306,8 @@ include::../gradle/packaging/boot-jar-layered-exclude-tools.gradle[tags=layered]
 include::../gradle/packaging/boot-jar-layered-exclude-tools.gradle.kts[tags=layered]
 ----
 
+
+
 [[packaging-layers-configuration]]
 ===== Custom Layers configuration
 Depending on your application, you may want to tune how layers are created and add new ones.

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

@@ -24,6 +24,7 @@ import org.gradle.api.plugins.BasePlugin;
 import org.gradle.api.plugins.JavaPlugin;
 import org.gradle.api.plugins.JavaPluginConvention;
 import org.gradle.api.tasks.SourceSet;
+import org.gradle.api.tasks.TaskContainer;
 import org.gradle.api.tasks.TaskProvider;
 import org.gradle.jvm.tasks.Jar;
 
@@ -91,15 +92,11 @@ public class SpringBootExtension {
 	 * @param configurer the task configurer
 	 */
 	public void buildInfo(Action<BuildInfo> configurer) {
-		TaskProvider<BuildInfo> bootBuildInfo = this.project.getTasks().register("bootBuildInfo", BuildInfo.class,
-				(task) -> {
-					task.setGroup(BasePlugin.BUILD_GROUP);
-					task.setDescription("Generates a META-INF/build-info.properties file.");
-					task.getConventionMapping().map("destinationDir",
-							() -> new File(determineMainSourceSetResourcesOutputDir(), "META-INF"));
-				});
+		TaskContainer tasks = this.project.getTasks();
+		TaskProvider<BuildInfo> bootBuildInfo = tasks.register("bootBuildInfo", BuildInfo.class,
+				this::configureBuildInfoTask);
 		this.project.getPlugins().withType(JavaPlugin.class, (plugin) -> {
-			this.project.getTasks().getByName(JavaPlugin.CLASSES_TASK_NAME).dependsOn(bootBuildInfo.get());
+			tasks.getByName(JavaPlugin.CLASSES_TASK_NAME).dependsOn(bootBuildInfo.get());
 			this.project.afterEvaluate((evaluated) -> {
 				BuildInfoProperties properties = bootBuildInfo.get().getProperties();
 				if (properties.getArtifact() == null) {
@@ -112,6 +109,13 @@ public class SpringBootExtension {
 		}
 	}
 
+	private void configureBuildInfoTask(BuildInfo task) {
+		task.setGroup(BasePlugin.BUILD_GROUP);
+		task.setDescription("Generates a META-INF/build-info.properties file.");
+		task.getConventionMapping().map("destinationDir",
+				() -> new File(determineMainSourceSetResourcesOutputDir(), "META-INF"));
+	}
+
 	private File determineMainSourceSetResourcesOutputDir() {
 		return this.project.getConvention().getPlugin(JavaPluginConvention.class).getSourceSets()
 				.getByName(SourceSet.MAIN_SOURCE_SET_NAME).getOutput().getResourcesDir();

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/BootJar.java

@@ -245,7 +245,7 @@ public class BootJar extends Jar implements BootArchive {
 			String coordinates = this.coordinatesByFileName.get(details.getName());
 			LibraryCoordinates libraryCoordinates = (coordinates != null) ? new LibraryCoordinates(coordinates)
 					: new LibraryCoordinates("?:?:?");
-			return this.layers.getLayer(new Library(null, details.getFile(), null, false, libraryCoordinates));
+			return this.layers.getLayer(new Library(null, details.getFile(), null, libraryCoordinates, false));
 		}
 		if (path.startsWith("BOOT-INF/classes/")) {
 			return this.layers.getLayer(details.getSourcePath());

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/LayerConfiguration.java

@@ -153,12 +153,6 @@ public class LayerConfiguration {
 
 	private static final class StrategySpec {
 
-		private enum TYPE {
-
-			LIBRARIES, RESOURCES;
-
-		}
-
 		private final TYPE type;
 
 		private List<LibraryFilter> libraryFilters;
@@ -232,6 +226,12 @@ public class LayerConfiguration {
 			return new StrategySpec(TYPE.RESOURCES);
 		}
 
+		private enum TYPE {
+
+			LIBRARIES, RESOURCES;
+
+		}
+
 	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Library.java

@@ -37,10 +37,10 @@ public class Library {
 
 	private final LibraryScope scope;
 
-	private final boolean unpackRequired;
-
 	private final LibraryCoordinates coordinates;
 
+	private final boolean unpackRequired;
+
 	/**
 	 * Create a new {@link Library}.
 	 * @param file the source file
@@ -69,15 +69,24 @@ public class Library {
 	 * @param unpackRequired if the library needs to be unpacked before it can be used
 	 */
 	public Library(String name, File file, LibraryScope scope, boolean unpackRequired) {
-		this(name, file, scope, unpackRequired, null);
+		this(name, file, scope, null, unpackRequired);
 	}
 
-	public Library(String name, File file, LibraryScope scope, boolean unpackRequired, LibraryCoordinates coordinates) {
+	/**
+	 * Create a new {@link Library}.
+	 * @param name the name of the library as it should be written or {@code null} to use
+	 * the file name
+	 * @param file the source file
+	 * @param scope the scope of the library
+	 * @param coordinates the library coordinates or {@code null}
+	 * @param unpackRequired if the library needs to be unpacked before it can be used
+	 */
+	public Library(String name, File file, LibraryScope scope, LibraryCoordinates coordinates, boolean unpackRequired) {
 		this.name = (name != null) ? name : file.getName();
 		this.file = file;
 		this.scope = scope;
-		this.unpackRequired = unpackRequired;
 		this.coordinates = coordinates;
+		this.unpackRequired = unpackRequired;
 	}
 
 	/**
@@ -113,6 +122,14 @@ public class Library {
 		return this.scope;
 	}
 
+	/**
+	 * Return the {@linkplain LibraryCoordinates coordinates} of the library.
+	 * @return the coordinates
+	 */
+	public LibraryCoordinates getCoordinates() {
+		return this.coordinates;
+	}
+
 	/**
 	 * Return if the file cannot be used directly as a nested jar and needs to be
 	 * unpacked.
@@ -122,14 +139,6 @@ public class Library {
 		return this.unpackRequired;
 	}
 
-	/**
-	 * Return the {@linkplain LibraryCoordinates coordinates} of the library.
-	 * @return the coordinates
-	 */
-	public LibraryCoordinates getCoordinates() {
-		return this.coordinates;
-	}
-
 	long getLastModified() {
 		return this.file.lastModified();
 	}

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/LibraryCoordinates.java

@@ -54,24 +54,45 @@ public final class LibraryCoordinates {
 		Assert.isTrue(elements.length >= 2, "Coordinates must contain at least 'groupId:artifactId'");
 		this.groupId = elements[0];
 		this.artifactId = elements[1];
-		if (elements.length > 2) {
-			this.version = elements[2];
-		}
-		else {
-			this.version = null;
-		}
+		this.version = (elements.length > 2) ? elements[2] : null;
 	}
 
+	/**
+	 * Return the group ID of the coordinates.
+	 * @return the group ID
+	 */
 	public String getGroupId() {
 		return this.groupId;
 	}
 
+	/**
+	 * Return the artifact ID of the coordinates.
+	 * @return the artifact ID
+	 */
 	public String getArtifactId() {
 		return this.artifactId;
 	}
 
+	/**
+	 * Return the version of the coordinates.
+	 * @return the version
+	 */
 	public String getVersion() {
 		return this.version;
 	}
 
+	/**
+	 * Return the coordinates in the form {@code groupId:artifactId:version}.
+	 */
+	@Override
+	public String toString() {
+		StringBuilder builder = new StringBuilder();
+		builder.append((this.groupId != null) ? this.groupId : "");
+		builder.append(":");
+		builder.append((this.artifactId != null) ? this.artifactId : "");
+		builder.append(":");
+		builder.append((this.version != null) ? this.version : "");
+		return builder.toString();
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/layer/library/CoordinateFilter.java

@@ -16,9 +16,9 @@
 
 package org.springframework.boot.loader.tools.layer.library;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
 import org.springframework.boot.loader.tools.Library;
 import org.springframework.boot.loader.tools.LibraryCoordinates;
@@ -32,58 +32,21 @@ import org.springframework.boot.loader.tools.LibraryCoordinates;
  */
 public class CoordinateFilter implements LibraryFilter {
 
-	private final List<String> includes = new ArrayList<>();
+	private static final String EMPTY_COORDINATES = "::";
 
-	private final List<String> excludes = new ArrayList<>();
+	private final List<Pattern> includes;
+
+	private final List<Pattern> excludes;
 
 	public CoordinateFilter(List<String> includes, List<String> excludes) {
-		this.includes.addAll(includes);
-		this.excludes.addAll(excludes);
+		this.includes = includes.stream().map(this::asPattern).collect(Collectors.toList());
+		this.excludes = excludes.stream().map(this::asPattern).collect(Collectors.toList());
 	}
 
-	@Override
-	public boolean isLibraryIncluded(Library library) {
-		return isMatch(library, this.includes);
-	}
-
-	@Override
-	public boolean isLibraryExcluded(Library library) {
-		return isMatch(library, this.excludes);
-	}
-
-	private boolean isMatch(Library library, List<String> toMatch) {
+	private Pattern asPattern(String string) {
 		StringBuilder builder = new StringBuilder();
-		LibraryCoordinates coordinates = library.getCoordinates();
-		if (coordinates != null) {
-			if (coordinates.getGroupId() != null) {
-				builder.append(coordinates.getGroupId());
-			}
-			builder.append(":");
-			if (coordinates.getArtifactId() != null) {
-				builder.append(coordinates.getArtifactId());
-			}
-			builder.append(":");
-			if (coordinates.getVersion() != null) {
-				builder.append(coordinates.getVersion());
-			}
-		}
-		else {
-			builder.append("::");
-		}
-		String input = builder.toString();
-		for (String patternString : toMatch) {
-			Pattern pattern = buildPatternForString(patternString);
-			if (pattern.matcher(input).matches()) {
-				return true;
-			}
-		}
-		return false;
-	}
-
-	private Pattern buildPatternForString(String pattern) {
-		StringBuilder builder = new StringBuilder();
-		for (int i = 0; i < pattern.length(); i++) {
-			char c = pattern.charAt(i);
+		for (int i = 0; i < string.length(); i++) {
+			char c = string.charAt(i);
 			if (c == '.') {
 				builder.append("\\.");
 			}
@@ -97,4 +60,25 @@ public class CoordinateFilter implements LibraryFilter {
 		return Pattern.compile(builder.toString());
 	}
 
+	@Override
+	public boolean isLibraryIncluded(Library library) {
+		return isMatch(library, this.includes);
+	}
+
+	@Override
+	public boolean isLibraryExcluded(Library library) {
+		return isMatch(library, this.excludes);
+	}
+
+	private boolean isMatch(Library library, List<Pattern> patterns) {
+		LibraryCoordinates coordinates = library.getCoordinates();
+		String input = (coordinates != null) ? coordinates.toString() : EMPTY_COORDINATES;
+		for (Pattern pattern : patterns) {
+			if (pattern.matcher(input).matches()) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/test/java/org/springframework/boot/loader/tools/LibraryCoordinatesTests.java

@@ -65,4 +65,10 @@ class LibraryCoordinatesTests {
 		assertThatIllegalArgumentException().isThrownBy(() -> new LibraryCoordinates("com.acme"));
 	}
 
+	@Test
+	void toStringReturnsString() {
+		assertThat(new LibraryCoordinates("com.acme:my-library:1.0.0")).hasToString("com.acme:my-library:1.0.0");
+		assertThat(new LibraryCoordinates("com.acme:my-library")).hasToString("com.acme:my-library:");
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/ArtifactsLibraries.java

@@ -82,7 +82,7 @@ public class ArtifactsLibraries implements Libraries {
 				}
 				LibraryCoordinates coordinates = new LibraryCoordinates(artifact.getGroupId(), artifact.getArtifactId(),
 						artifact.getVersion());
-				callback.library(new Library(name, artifact.getFile(), scope, isUnpackRequired(artifact), coordinates));
+				callback.library(new Library(name, artifact.getFile(), scope, coordinates, isUnpackRequired(artifact)));
 			}
 		}
 	}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/CustomLayersProvider.java

@@ -35,6 +35,7 @@ import org.springframework.boot.loader.tools.layer.library.CoordinateFilter;
 import org.springframework.boot.loader.tools.layer.library.FilteredLibraryStrategy;
 import org.springframework.boot.loader.tools.layer.library.LibraryFilter;
 import org.springframework.boot.loader.tools.layer.library.LibraryStrategy;
+import org.springframework.util.Assert;
 
 /**
  * Produces a {@link CustomLayers} based on the given {@link Document}.
@@ -46,12 +47,12 @@ public class CustomLayersProvider {
 
 	public CustomLayers getLayers(Document document) {
 		Element root = document.getDocumentElement();
-		NodeList nl = root.getChildNodes();
+		NodeList nodes = root.getChildNodes();
 		List<Layer> layers = new ArrayList<>();
 		List<LibraryStrategy> libraryStrategies = new ArrayList<>();
 		List<ResourceStrategy> resourceStrategies = new ArrayList<>();
-		for (int i = 0; i < nl.getLength(); i++) {
-			Node node = nl.item(i);
+		for (int i = 0; i < nodes.getLength(); i++) {
+			Node node = nodes.item(i);
 			if (node instanceof Element) {
 				processNode(layers, libraryStrategies, resourceStrategies, (Element) node);
 			}
@@ -80,14 +81,13 @@ public class CustomLayersProvider {
 
 	private List<Layer> getLayers(Element element) {
 		List<Layer> layers = new ArrayList<>();
-		NodeList nodes = element.getChildNodes();
-		for (int i = 0; i < nodes.getLength(); i++) {
-			Node node = nodes.item(i);
-			if (node instanceof Element) {
-				Element ele = (Element) node;
-				String nodeName = ele.getNodeName();
-				if ("layer".equals(nodeName)) {
-					layers.add(new Layer(ele.getTextContent()));
+		NodeList childNodes = element.getChildNodes();
+		for (int i = 0; i < childNodes.getLength(); i++) {
+			Node childNode = childNodes.item(i);
+			if (childNode instanceof Element) {
+				Element childElement = (Element) childNode;
+				if ("layer".equals(childElement.getNodeName())) {
+					layers.add(new Layer(childElement.getTextContent()));
 				}
 			}
 		}
@@ -98,26 +98,11 @@ public class CustomLayersProvider {
 			FilterFactory<E> filterFactory, Predicate<String> filterPredicate) {
 		List<T> contents = new ArrayList<>();
 		for (int i = 0; i < nodes.getLength(); i++) {
-			Node item = nodes.item(i);
-			if (item instanceof Element) {
-				Element element = (Element) item;
+			Node node = nodes.item(i);
+			if (node instanceof Element) {
+				Element element = (Element) node;
 				if ("layer-content".equals(element.getTagName())) {
-					NodeList filterList = item.getChildNodes();
-					if (filterList.getLength() == 0) {
-						throw new IllegalArgumentException("Filters for layer-content must not be empty.");
-					}
-					List<E> filters = new ArrayList<>();
-					for (int j = 0; j < filterList.getLength(); j++) {
-						Node filterNode = filterList.item(j);
-						if (filterNode instanceof Element) {
-							List<String> includeList = getPatterns((Element) filterNode, "include");
-							List<String> excludeList = getPatterns((Element) filterNode, "exclude");
-							if (filterPredicate.test(filterNode.getNodeName())) {
-								E filter = filterFactory.getFilter(includeList, excludeList);
-								filters.add(filter);
-							}
-						}
-					}
+					List<E> filters = getFilters(node, filterFactory, filterPredicate);
 					String layer = element.getAttribute("layer");
 					contents.add(strategyFactory.getStrategy(layer, filters));
 				}
@@ -126,16 +111,33 @@ public class CustomLayersProvider {
 		return contents;
 	}
 
-	private List<String> getPatterns(Element element, String key) {
-		NodeList patterns = element.getElementsByTagName(key);
-		List<String> values = new ArrayList<>();
-		for (int j = 0; j < patterns.getLength(); j++) {
-			Node item = patterns.item(j);
-			if (item instanceof Element) {
-				values.add(item.getTextContent());
+	private <E> List<E> getFilters(Node node, FilterFactory<E> factory, Predicate<String> predicate) {
+		NodeList childNodes = node.getChildNodes();
+		Assert.state(childNodes.getLength() > 0, "Filters for layer-content must not be empty.");
+		List<E> filters = new ArrayList<>();
+		for (int i = 0; i < childNodes.getLength(); i++) {
+			Node childNode = childNodes.item(i);
+			if (childNode instanceof Element) {
+				List<String> include = getPatterns((Element) childNode, "include");
+				List<String> exclude = getPatterns((Element) childNode, "exclude");
+				if (predicate.test(childNode.getNodeName())) {
+					filters.add(factory.getFilter(include, exclude));
+				}
 			}
 		}
-		return values;
+		return filters;
+	}
+
+	private List<String> getPatterns(Element element, String key) {
+		List<String> patterns = new ArrayList<>();
+		NodeList nodes = element.getElementsByTagName(key);
+		for (int j = 0; j < nodes.getLength(); j++) {
+			Node node = nodes.item(j);
+			if (node instanceof Element) {
+				patterns.add(node.getTextContent());
+			}
+		}
+		return patterns;
 	}
 
 	interface StrategyFactory<E, T> {

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RepackageMojo.java

@@ -186,14 +186,16 @@ public class RepackageMojo extends AbstractPackagerMojo {
 		if (this.outputTimestamp == null || this.outputTimestamp.length() < 2) {
 			return null;
 		}
-		long epochSeconds;
+		return FileTime.from(getOutputTimestampEpochSeconds(), TimeUnit.SECONDS);
+	}
+
+	private long getOutputTimestampEpochSeconds() {
 		try {
-			epochSeconds = Long.parseLong(this.outputTimestamp);
+			return Long.parseLong(this.outputTimestamp);
 		}
 		catch (NumberFormatException ex) {
-			epochSeconds = OffsetDateTime.parse(this.outputTimestamp).toInstant().getEpochSecond();
+			return OffsetDateTime.parse(this.outputTimestamp).toInstant().getEpochSecond();
 		}
-		return FileTime.from(epochSeconds, TimeUnit.SECONDS);
 	}
 
 	/**

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/test/java/org/springframework/boot/maven/CustomLayersProviderTests.java

@@ -30,7 +30,7 @@ import org.springframework.boot.loader.tools.layer.CustomLayers;
 import org.springframework.core.io.ClassPathResource;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
 
@@ -74,14 +74,14 @@ public class CustomLayersProviderTests {
 
 	@Test
 	void getLayerResolverWhenDocumentContainsLibraryLayerWithNoFilters() {
-		assertThatIllegalArgumentException()
+		assertThatIllegalStateException()
 				.isThrownBy(() -> this.customLayersProvider.getLayers(getDocument("library-layer-no-filter.xml")))
 				.withMessage("Filters for layer-content must not be empty.");
 	}
 
 	@Test
 	void getLayerResolverWhenDocumentContainsResourceLayerWithNoFilters() {
-		assertThatIllegalArgumentException()
+		assertThatIllegalStateException()
 				.isThrownBy(() -> this.customLayersProvider.getLayers(getDocument("resource-layer-no-filter.xml")))
 				.withMessage("Filters for layer-content must not be empty.");
 	}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/availability/ApplicationAvailabilityProvider.java

@@ -18,6 +18,7 @@ package org.springframework.boot.availability;
 
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationListener;
+import org.springframework.util.Assert;
 
 /**
  * Holds the availability state of the application.
@@ -36,19 +37,38 @@ public class ApplicationAvailabilityProvider implements ApplicationListener<Appl
 
 	private ReadinessState readinessState;
 
+	/**
+	 * Create a new {@link ApplicationAvailabilityProvider} instance with
+	 * {@link LivenessState#broken()} and {@link ReadinessState#unready()}.
+	 */
 	public ApplicationAvailabilityProvider() {
 		this(LivenessState.broken(), ReadinessState.unready());
 	}
 
+	/**
+	 * Create a new {@link ApplicationAvailabilityProvider} with the given states.
+	 * @param livenessState the liveness state
+	 * @param readinessState the readiness state
+	 */
 	public ApplicationAvailabilityProvider(LivenessState livenessState, ReadinessState readinessState) {
+		Assert.notNull(livenessState, "LivenessState must not be null");
+		Assert.notNull(readinessState, "ReadinessState must not be null");
 		this.livenessState = livenessState;
 		this.readinessState = readinessState;
 	}
 
+	/**
+	 * Return the {@link LivenessState} of the application.
+	 * @return the liveness state
+	 */
 	public LivenessState getLivenessState() {
 		return this.livenessState;
 	}
 
+	/**
+	 * Return the {@link ReadinessState} of the application.
+	 * @return the readiness state
+	 */
 	public ReadinessState getReadinessState() {
 		return this.readinessState;
 	}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/availability/LivenessState.java

@@ -41,15 +41,14 @@ public final class LivenessState {
 	}
 
 	@Override
-	public boolean equals(Object o) {
-		if (this == o) {
+	public boolean equals(Object obj) {
+		if (this == obj) {
 			return true;
 		}
-		if (o == null || getClass() != o.getClass()) {
+		if (obj == null || getClass() != obj.getClass()) {
 			return false;
 		}
-		LivenessState that = (LivenessState) o;
-		return this.status == that.status;
+		return this.status == ((LivenessState) obj).status;
 	}
 
 	@Override
@@ -76,6 +75,7 @@ public final class LivenessState {
 		 * The application is running and its internal state is correct.
 		 */
 		LIVE,
+
 		/**
 		 * The internal state of the application is broken.
 		 */

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/availability/ReadinessState.java

@@ -41,15 +41,14 @@ public final class ReadinessState {
 	}
 
 	@Override
-	public boolean equals(Object o) {
-		if (this == o) {
+	public boolean equals(Object obj) {
+		if (this == obj) {
 			return true;
 		}
-		if (o == null || getClass() != o.getClass()) {
+		if (obj == null || getClass() != obj.getClass()) {
 			return false;
 		}
-		ReadinessState that = (ReadinessState) o;
-		return this.availability == that.availability;
+		return this.availability == ((ReadinessState) obj).availability;
 	}
 
 	@Override
@@ -76,6 +75,7 @@ public final class ReadinessState {
 		 * The application is not willing to receive traffic.
 		 */
 		UNREADY,
+
 		/**
 		 * The application is ready to receive traffic.
 		 */

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyGracefulShutdown.java

@@ -55,15 +55,7 @@ class JettyGracefulShutdown implements GracefulShutdown {
 		logger.info("Commencing graceful shutdown, allowing up to " + this.period.getSeconds()
 				+ "s for active requests to complete");
 		for (Connector connector : this.server.getConnectors()) {
-			try {
-				connector.shutdown().get();
-			}
-			catch (InterruptedException ex) {
-				Thread.currentThread().interrupt();
-			}
-			catch (ExecutionException ex) {
-				// Continue
-			}
+			shutdown(connector);
 		}
 		this.shuttingDown = true;
 		long end = System.currentTimeMillis() + this.period.toMillis();
@@ -87,6 +79,18 @@ class JettyGracefulShutdown implements GracefulShutdown {
 		return activeRequests == 0;
 	}
 
+	private void shutdown(Connector connector) {
+		try {
+			connector.shutdown().get();
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
+		catch (ExecutionException ex) {
+			// Continue
+		}
+	}
+
 	@Override
 	public boolean isShuttingDown() {
 		return this.shuttingDown;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyWebServer.java

@@ -37,7 +37,6 @@ import org.eclipse.jetty.server.handler.StatisticsHandler;
 import org.eclipse.jetty.util.component.AbstractLifeCycle;
 
 import org.springframework.boot.web.server.GracefulShutdown;
-import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -101,20 +100,20 @@ public class JettyWebServer implements WebServer {
 		this.autoStart = autoStart;
 		Assert.notNull(server, "Jetty Server must not be null");
 		this.server = server;
-		GracefulShutdown gracefulShutdown = null;
-		if (shutdownGracePeriod != null) {
-			StatisticsHandler handler = new StatisticsHandler();
-			handler.setHandler(server.getHandler());
-			server.setHandler(handler);
-			gracefulShutdown = new JettyGracefulShutdown(server, handler::getRequestsActive, shutdownGracePeriod);
-		}
-		else {
-			gracefulShutdown = new ImmediateGracefulShutdown();
-		}
-		this.gracefulShutdown = gracefulShutdown;
+		this.gracefulShutdown = createGracefulShutdown(server, shutdownGracePeriod);
 		initialize();
 	}
 
+	private GracefulShutdown createGracefulShutdown(Server server, Duration shutdownGracePeriod) {
+		if (shutdownGracePeriod == null) {
+			return GracefulShutdown.IMMEDIATE;
+		}
+		StatisticsHandler handler = new StatisticsHandler();
+		handler.setHandler(server.getHandler());
+		server.setHandler(handler);
+		return new JettyGracefulShutdown(server, handler::getRequestsActive, shutdownGracePeriod);
+	}
+
 	private void initialize() {
 		synchronized (this.monitor) {
 			try {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyGracefulShutdown.java

@@ -55,12 +55,7 @@ final class NettyGracefulShutdown implements GracefulShutdown {
 		}
 		this.shuttingDown = true;
 		try {
-			if (this.period != null) {
-				server.disposeNow(this.period);
-			}
-			else {
-				server.disposeNow();
-			}
+			disposeNow(server);
 			logger.info("Graceful shutdown complete");
 			return true;
 		}
@@ -73,6 +68,15 @@ final class NettyGracefulShutdown implements GracefulShutdown {
 		}
 	}
 
+	private void disposeNow(DisposableServer server) {
+		if (this.period != null) {
+			server.disposeNow(this.period);
+		}
+		else {
+			server.disposeNow();
+		}
+	}
+
 	@Override
 	public boolean isShuttingDown() {
 		return this.shuttingDown;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyWebServer.java

@@ -35,7 +35,6 @@ import reactor.netty.http.server.HttpServerResponse;
 import reactor.netty.http.server.HttpServerRoutes;
 
 import org.springframework.boot.web.server.GracefulShutdown;
-import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -96,7 +95,7 @@ public class NettyWebServer implements WebServer {
 		}
 		else {
 			this.httpServer = httpServer;
-			this.shutdown = new ImmediateGracefulShutdown();
+			this.shutdown = GracefulShutdown.IMMEDIATE;
 		}
 	}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatWebServer.java

@@ -40,7 +40,6 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.naming.ContextBindings;
 
 import org.springframework.boot.web.server.GracefulShutdown;
-import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -102,7 +101,7 @@ public class TomcatWebServer implements WebServer {
 		this.tomcat = tomcat;
 		this.autoStart = autoStart;
 		this.gracefulShutdown = (shutdownGracePeriod != null) ? new TomcatGracefulShutdown(tomcat, shutdownGracePeriod)
-				: new ImmediateGracefulShutdown();
+				: GracefulShutdown.IMMEDIATE;
 		initialize();
 	}
 

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowReactiveWebServerFactory.java

@@ -41,7 +41,6 @@ import org.xnio.XnioWorker;
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.server.ReactiveWebServerFactory;
 import org.springframework.boot.web.server.GracefulShutdown;
-import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.http.server.reactive.UndertowHttpHandlerAdapter;
 import org.springframework.util.Assert;
@@ -103,12 +102,12 @@ public class UndertowReactiveWebServerFactory extends AbstractReactiveWebServerF
 		}
 		handler = UndertowCompressionConfigurer.configureCompression(getCompression(), handler);
 		Closeable closeable = null;
-		GracefulShutdown gracefulShutdown = null;
 		if (isAccessLogEnabled()) {
 			AccessLogHandlerConfiguration accessLogHandlerConfiguration = configureAccessLogHandler(builder, handler);
 			closeable = accessLogHandlerConfiguration.closeable;
 			handler = accessLogHandlerConfiguration.accessLogHandler;
 		}
+		GracefulShutdown gracefulShutdown = null;
 		GracefulShutdownHandler gracefulShutdownHandler = Handlers.gracefulShutdown(handler);
 		Duration gracePeriod = getShutdown().getGracePeriod();
 		if (gracePeriod != null) {
@@ -116,7 +115,7 @@ public class UndertowReactiveWebServerFactory extends AbstractReactiveWebServerF
 			handler = gracefulShutdownHandler;
 		}
 		else {
-			gracefulShutdown = new ImmediateGracefulShutdown();
+			gracefulShutdown = GracefulShutdown.IMMEDIATE;
 		}
 		builder.setHandler(handler);
 		return new UndertowWebServer(builder, getPort() >= 0, closeable, gracefulShutdown);

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowServletWebServer.java

@@ -38,7 +38,6 @@ import org.xnio.channels.BoundChannel;
 
 import org.springframework.boot.web.server.Compression;
 import org.springframework.boot.web.server.GracefulShutdown;
-import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -234,7 +233,7 @@ public class UndertowServletWebServer implements WebServer {
 			httpHandler = gracefulShutdownHandler;
 		}
 		else {
-			this.gracefulShutdown = new ImmediateGracefulShutdown();
+			this.gracefulShutdown = GracefulShutdown.IMMEDIATE;
 		}
 		this.builder.setHandler(httpHandler);
 		return this.builder.build();

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowWebServer.java

@@ -30,7 +30,6 @@ import org.apache.commons.logging.LogFactory;
 import org.xnio.channels.BoundChannel;
 
 import org.springframework.boot.web.server.GracefulShutdown;
-import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -84,7 +83,7 @@ public class UndertowWebServer implements WebServer {
 	 * @since 2.0.4
 	 */
 	public UndertowWebServer(Undertow.Builder builder, boolean autoStart, Closeable closeable) {
-		this(builder, autoStart, closeable, new ImmediateGracefulShutdown());
+		this(builder, autoStart, closeable, GracefulShutdown.IMMEDIATE);
 	}
 
 	/**

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/server/GracefulShutdown.java

@@ -24,6 +24,11 @@ package org.springframework.boot.web.server;
  */
 public interface GracefulShutdown {
 
+	/**
+	 * A {@link GracefulShutdown} that returns immediately with no grace period.
+	 */
+	GracefulShutdown IMMEDIATE = new ImmediateGracefulShutdown();
+
 	/**
 	 * Shuts down the {@link WebServer}, returning {@code true} if activity ceased during
 	 * the grace period, otherwise {@code false}.

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/server/ImmediateGracefulShutdown.java

@@ -20,9 +20,8 @@ package org.springframework.boot.web.server;
  * A {@link GracefulShutdown} that returns immediately with no grace period.
  *
  * @author Andy Wilkinson
- * @since 2.3.0
  */
-public class ImmediateGracefulShutdown implements GracefulShutdown {
+class ImmediateGracefulShutdown implements GracefulShutdown {
 
 	@Override
 	public boolean shutDownGracefully() {