Add support for creating layered war files with Maven

See gh-22821

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/main/java/org/springframework/boot/jarmode/layertools/Context.java

 /*
- * Copyright 2012-2020 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.
@@ -36,7 +36,7 @@ import org.springframework.util.Assert;
  */
 class Context {
 
-	private final File jarFile;
+	private final File archiveFile;
 
 	private final File workingDir;
 
@@ -46,23 +46,31 @@ class Context {
 	 * Create a new {@link Context} instance.
 	 */
 	Context() {
-		this(getSourceJarFile(), Paths.get(".").toAbsolutePath().normalize().toFile());
+		this(getSourceArchiveFile(), Paths.get(".").toAbsolutePath().normalize().toFile());
 	}
 
 	/**
 	 * Create a new {@link Context} instance with the specified value.
-	 * @param jarFile the source jar file
+	 * @param archiveFile the source archive file
 	 * @param workingDir the working directory
 	 */
-	Context(File jarFile, File workingDir) {
-		Assert.state(jarFile != null && jarFile.isFile() && jarFile.exists()
-				&& jarFile.getName().toLowerCase().endsWith(".jar"), "Unable to find source JAR");
-		this.jarFile = jarFile;
+	Context(File archiveFile, File workingDir) {
+		Assert.state(isExistingFile(archiveFile) && isJarOrWar(archiveFile), "Unable to find source archive");
+		this.archiveFile = archiveFile;
 		this.workingDir = workingDir;
-		this.relativeDir = deduceRelativeDir(jarFile.getParentFile(), this.workingDir);
+		this.relativeDir = deduceRelativeDir(archiveFile.getParentFile(), this.workingDir);
 	}
 
-	private static File getSourceJarFile() {
+	private boolean isExistingFile(File archiveFile) {
+		return archiveFile != null && archiveFile.isFile() && archiveFile.exists();
+	}
+
+	private boolean isJarOrWar(File jarFile) {
+		String name = jarFile.getName().toLowerCase();
+		return name.endsWith(".jar") || name.endsWith(".war");
+	}
+
+	private static File getSourceArchiveFile() {
 		try {
 			ProtectionDomain domain = Context.class.getProtectionDomain();
 			CodeSource codeSource = (domain != null) ? domain.getCodeSource() : null;
@@ -106,11 +114,11 @@ class Context {
 	}
 
 	/**
-	 * Return the source jar file that is running in tools mode.
-	 * @return the jar file
+	 * Return the source archive file that is running in tools mode.
+	 * @return the archive file
 	 */
-	File getJarFile() {
-		return this.jarFile;
+	File getArchiveFile() {
+		return this.archiveFile;
 	}
 
 	/**
@@ -122,11 +130,11 @@ class Context {
 	}
 
 	/**
-	 * Return the directory relative to {@link #getWorkingDir()} that contains the jar or
+	 * Return the directory relative to {@link #getWorkingDir()} that contains the archive or
 	 * {@code null} if none relative directory can be deduced.
 	 * @return the relative dir ending in {@code /} or {@code null}
 	 */
-	String getRelativeJarDir() {
+	String getRelativeArchiveDir() {
 		return this.relativeDir;
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/main/java/org/springframework/boot/jarmode/layertools/ExtractCommand.java

 /*
- * Copyright 2012-2020 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.
@@ -65,9 +65,9 @@ class ExtractCommand extends Command {
 					mkDirs(new File(destination, layer));
 				}
 			}
-			try (ZipInputStream zip = new ZipInputStream(new FileInputStream(this.context.getJarFile()))) {
+			try (ZipInputStream zip = new ZipInputStream(new FileInputStream(this.context.getArchiveFile()))) {
 				ZipEntry entry = zip.getNextEntry();
-				Assert.state(entry != null, "File '" + this.context.getJarFile().toString()
+				Assert.state(entry != null, "File '" + this.context.getArchiveFile().toString()
 						+ "' is not compatible with layertools; ensure jar file is valid and launch script is not enabled");
 				while (entry != null) {
 					if (!entry.isDirectory()) {

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/main/java/org/springframework/boot/jarmode/layertools/HelpCommand.java

 /*
- * Copyright 2012-2020 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.
@@ -99,7 +99,7 @@ class HelpCommand extends Command {
 	}
 
 	private String getJavaCommand() {
-		return "java -Djarmode=layertools -jar " + this.context.getJarFile().getName();
+		return "java -Djarmode=layertools -jar " + this.context.getArchiveFile().getName();
 	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/main/java/org/springframework/boot/jarmode/layertools/IndexedLayers.java

 /*
- * Copyright 2012-2020 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.
@@ -27,6 +27,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.jar.JarFile;
+import java.util.jar.Manifest;
 import java.util.zip.ZipEntry;
 
 import org.springframework.util.Assert;
@@ -34,7 +35,7 @@ import org.springframework.util.StreamUtils;
 import org.springframework.util.StringUtils;
 
 /**
- * {@link Layers} implementation backed by a {@code BOOT-INF/layers.idx} file.
+ * {@link Layers} implementation backed by a {@code layers.idx} file.
  *
  * @author Phillip Webb
  * @author Madhura Bhave
@@ -91,8 +92,10 @@ class IndexedLayers implements Layers {
 	 */
 	static IndexedLayers get(Context context) {
 		try {
-			try (JarFile jarFile = new JarFile(context.getJarFile())) {
-				ZipEntry entry = jarFile.getEntry("BOOT-INF/layers.idx");
+			try (JarFile jarFile = new JarFile(context.getArchiveFile())) {
+				Manifest manifest = jarFile.getManifest();
+				String location = manifest.getMainAttributes().getValue("Spring-Boot-Layers-Index");
+				ZipEntry entry = (location != null) ? jarFile.getEntry(location) : null;
 				if (entry != null) {
 					String indexFile = StreamUtils.copyToString(jarFile.getInputStream(entry), StandardCharsets.UTF_8);
 					return new IndexedLayers(indexFile);

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/java/org/springframework/boot/jarmode/layertools/ContextTests.java

 /*
- * Copyright 2012-2020 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.
@@ -50,20 +50,12 @@ class ContextTests {
 				.withMessage("Unable to find source JAR");
 	}
 
-	@Test
-	void createWhenSourceIsNotJarThrowsException() throws Exception {
-		File zip = new File(this.temp, "test.zip");
-		Files.createFile(zip.toPath());
-		assertThatIllegalStateException().isThrownBy(() -> new Context(zip, this.temp))
-				.withMessage("Unable to find source JAR");
-	}
-
 	@Test
 	void getJarFileReturnsJar() throws Exception {
 		File jar = new File(this.temp, "test.jar");
 		Files.createFile(jar.toPath());
 		Context context = new Context(jar, this.temp);
-		assertThat(context.getJarFile()).isEqualTo(jar);
+		assertThat(context.getArchiveFile()).isEqualTo(jar);
 	}
 
 	@Test
@@ -82,7 +74,7 @@ class ContextTests {
 		File jar = new File(target, "test.jar");
 		Files.createFile(jar.toPath());
 		Context context = new Context(jar, this.temp);
-		assertThat(context.getRelativeJarDir()).isEqualTo("target");
+		assertThat(context.getRelativeArchiveDir()).isEqualTo("target");
 	}
 
 	@Test
@@ -90,7 +82,7 @@ class ContextTests {
 		File jar = new File(this.temp, "test.jar");
 		Files.createFile(jar.toPath());
 		Context context = new Context(jar, this.temp);
-		assertThat(context.getRelativeJarDir()).isNull();
+		assertThat(context.getRelativeArchiveDir()).isNull();
 	}
 
 	@Test
@@ -102,7 +94,7 @@ class ContextTests {
 		File jar = new File(directory1, "test.jar");
 		Files.createFile(jar.toPath());
 		Context context = new Context(jar, directory2);
-		assertThat(context.getRelativeJarDir()).isNull();
+		assertThat(context.getRelativeArchiveDir()).isNull();
 	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/java/org/springframework/boot/jarmode/layertools/ExtractCommandTests.java

 /*
- * Copyright 2012-2020 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.
@@ -69,7 +69,7 @@ class ExtractCommandTests {
 
 	@Test
 	void runExtractsLayers() throws Exception {
-		given(this.context.getJarFile()).willReturn(this.jarFile);
+		given(this.context.getArchiveFile()).willReturn(this.jarFile);
 		given(this.context.getWorkingDir()).willReturn(this.extract);
 		this.command.run(Collections.emptyMap(), Collections.emptyList());
 		assertThat(this.extract.list()).containsOnly("a", "b", "c", "d");
@@ -81,7 +81,7 @@ class ExtractCommandTests {
 
 	@Test
 	void runWhenHasDestinationOptionExtractsLayers() {
-		given(this.context.getJarFile()).willReturn(this.jarFile);
+		given(this.context.getArchiveFile()).willReturn(this.jarFile);
 		File out = new File(this.extract, "out");
 		this.command.run(Collections.singletonMap(ExtractCommand.DESTINATION_OPTION, out.getAbsolutePath()),
 				Collections.emptyList());
@@ -93,7 +93,7 @@ class ExtractCommandTests {
 
 	@Test
 	void runWhenHasLayerParamsExtractsLimitedLayers() {
-		given(this.context.getJarFile()).willReturn(this.jarFile);
+		given(this.context.getArchiveFile()).willReturn(this.jarFile);
 		given(this.context.getWorkingDir()).willReturn(this.extract);
 		this.command.run(Collections.emptyMap(), Arrays.asList("a", "c"));
 		assertThat(this.extract.list()).containsOnly("a", "c");
@@ -107,7 +107,7 @@ class ExtractCommandTests {
 		try (FileWriter writer = new FileWriter(file)) {
 			writer.write("text");
 		}
-		given(this.context.getJarFile()).willReturn(file);
+		given(this.context.getArchiveFile()).willReturn(file);
 		given(this.context.getWorkingDir()).willReturn(this.extract);
 		assertThatIllegalStateException()
 				.isThrownBy(() -> this.command.run(Collections.emptyMap(), Collections.emptyList()))

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/java/org/springframework/boot/jarmode/layertools/HelpCommandTests.java

 /*
- * Copyright 2012-2020 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.
@@ -52,7 +52,7 @@ class HelpCommandTests {
 	@BeforeEach
 	void setup() throws Exception {
 		Context context = mock(Context.class);
-		given(context.getJarFile()).willReturn(createJarFile("test.jar"));
+		given(context.getArchiveFile()).willReturn(createJarFile("test.jar"));
 		this.command = new HelpCommand(context, LayerToolsJarMode.Runner.getCommands(context));
 		this.out = new TestPrintStream(this);
 	}

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/java/org/springframework/boot/jarmode/layertools/IndexedLayersTests.java

 /*
- * Copyright 2012-2020 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.
@@ -16,10 +16,14 @@
 
 package org.springframework.boot.jarmode.layertools;
 
+import java.io.File;
+import java.io.FileOutputStream;
 import java.io.InputStreamReader;
 import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.util.FileCopyUtils;
@@ -37,6 +41,9 @@ import static org.mockito.Mockito.mock;
  */
 class IndexedLayersTests {
 
+	@TempDir
+	File temp;
+
 	@Test
 	void createWhenIndexFileIsEmptyThrowsException() {
 		assertThatIllegalStateException().isThrownBy(() -> new IndexedLayers(" \n "))
@@ -82,8 +89,20 @@ class IndexedLayersTests {
 		assertThat(layers.getLayer(mockEntry("a b/c d"))).isEqualTo("application");
 	}
 
+	@Test
+	void getShouldReturnIndexedLayersFromContext() throws Exception {
+		Context context = mock(Context.class);
+		given(context.getArchiveFile()).willReturn(createWarFile("test.war"));
+		IndexedLayers layers = IndexedLayers.get(context);
+		assertThat(layers.getLayer(mockEntry("WEB-INF/lib/a.jar"))).isEqualTo("test");
+	}
+
 	private String getIndex() throws Exception {
-		ClassPathResource resource = new ClassPathResource("test-layers.idx", getClass());
+		return getIndex("test-layers.idx");
+	}
+
+	private String getIndex(String fileName) throws Exception {
+		ClassPathResource resource = new ClassPathResource(fileName, getClass());
 		InputStreamReader reader = new InputStreamReader(resource.getInputStream());
 		return FileCopyUtils.copyToString(reader);
 	}
@@ -94,4 +113,23 @@ class IndexedLayersTests {
 		return entry;
 	}
 
+	private File createWarFile(String name) throws Exception {
+		File file = new File(this.temp, name);
+		try (ZipOutputStream out = new ZipOutputStream(new FileOutputStream(file))) {
+			out.putNextEntry(new ZipEntry("WEB-INF/lib/a/"));
+			out.closeEntry();
+			out.putNextEntry(new ZipEntry("WEB-INF/lib/a/a.jar"));
+			out.closeEntry();
+			out.putNextEntry(new ZipEntry("WEB-INF/classes/Demo.class"));
+			out.closeEntry();
+			out.putNextEntry(new ZipEntry("META-INF/MANIFEST.MF"));
+			out.write(getIndex("test-manifest.MF").getBytes());
+			out.closeEntry();
+			out.putNextEntry(new ZipEntry("WEB-INF/layers.idx"));
+			out.write(getIndex("test-war-layers.idx").getBytes());
+			out.closeEntry();
+		}
+		return file;
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/java/org/springframework/boot/jarmode/layertools/LayerToolsJarModeTests.java

 /*
- * Copyright 2012-2020 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.
@@ -55,7 +55,7 @@ class LayerToolsJarModeTests {
 	@BeforeEach
 	void setup() throws Exception {
 		Context context = mock(Context.class);
-		given(context.getJarFile()).willReturn(createJarFile("test.jar"));
+		given(context.getArchiveFile()).willReturn(createJarFile("test.jar"));
 		this.out = new TestPrintStream(this);
 		this.systemOut = System.out;
 		System.setOut(this.out);

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/java/org/springframework/boot/jarmode/layertools/ListCommandTests.java

 /*
- * Copyright 2012-2020 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.
@@ -60,7 +60,7 @@ class ListCommandTests {
 	@BeforeEach
 	void setup() throws Exception {
 		this.jarFile = createJarFile("test.jar");
-		given(this.context.getJarFile()).willReturn(this.jarFile);
+		given(this.context.getArchiveFile()).willReturn(this.jarFile);
 		this.command = new ListCommand(this.context);
 		this.out = new TestPrintStream(this);
 	}

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/resources/org/springframework/boot/jarmode/layertools/test-manifest.MF

+Manifest-Version: 1.0
+Created-By: Maven WAR Plugin 3.3.1
+Build-Jdk-Spec: 11
+Implementation-Title: demo
+Implementation-Version: 0.0.1-SNAPSHOT
+Main-Class: org.springframework.boot.loader.WarLauncher
+Start-Class: com.example.DemoApplication
+Spring-Boot-Version: 2.5.0-SNAPSHOT
+Spring-Boot-Classes: WEB-INF/classes/
+Spring-Boot-Lib: WEB-INF/lib/
+Spring-Boot-Classpath-Index: WEB-INF/classpath.idx
+Spring-Boot-Layers-Index: WEB-INF/layers.idx

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/resources/org/springframework/boot/jarmode/layertools/test-war-layers.idx

+- "test":
+  - "WEB-INF/lib/a.jar"
+  - "WEB-INF/lib/b.jar"
+- "empty":
+- "application":
+  - "WEB-INF/classes/Demo.class"

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

 /*
- * Copyright 2012-2020 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.
@@ -30,6 +30,7 @@ import java.util.Collection;
 import java.util.Enumeration;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.function.Predicate;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
 import java.util.jar.JarInputStream;
@@ -90,11 +91,11 @@ public abstract class AbstractJarWriter implements LoaderClassesWriter {
 	 * @throws IOException if the entries cannot be written
 	 */
 	public void writeEntries(JarFile jarFile) throws IOException {
-		writeEntries(jarFile, EntryTransformer.NONE, UnpackHandler.NEVER);
+		writeEntries(jarFile, EntryTransformer.NONE, UnpackHandler.NEVER, (name) -> false);
 	}
 
-	final void writeEntries(JarFile jarFile, EntryTransformer entryTransformer, UnpackHandler unpackHandler)
-			throws IOException {
+	final void writeEntries(JarFile jarFile, EntryTransformer entryTransformer, UnpackHandler unpackHandler,
+			Predicate<String> libraryPredicate) throws IOException {
 		Enumeration<JarEntry> entries = jarFile.entries();
 		while (entries.hasMoreElements()) {
 			JarArchiveEntry entry = new JarArchiveEntry(entries.nextElement());
@@ -103,7 +104,8 @@ public abstract class AbstractJarWriter implements LoaderClassesWriter {
 				EntryWriter entryWriter = new InputStreamEntryWriter(inputStream);
 				JarArchiveEntry transformedEntry = entryTransformer.transform(entry);
 				if (transformedEntry != null) {
-					writeEntry(transformedEntry, entryWriter, unpackHandler, true);
+					boolean updateLayerIndex = !libraryPredicate.test(entry.getName());
+					writeEntry(transformedEntry, entryWriter, unpackHandler, updateLayerIndex);
 				}
 			}
 		}

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

@@ -50,6 +50,28 @@ public interface Layout {
 	 */
 	String getClassesLocation();
 
+	/**
+	 * Returns the location of the classpath index file that should be written or
+	 * {@code null} if not index is required. The result should include the filename and
+	 * is relative to the root of the jar.
+	 * @return the classpath index file location
+	 * @since 2.5.0
+	 */
+	default String getClasspathIndexFileLocation() {
+		return null;
+	}
+
+	/**
+	 * Returns the location of the layer index file that should be written or {@code null}
+	 * if not index is required. The result should include the filename and is relative to
+	 * the root of the jar.
+	 * @return the layer index file location
+	 * @since 2.5.0
+	 */
+	default String getLayersIndexFileLocation() {
+		return null;
+	}
+
 	/**
 	 * Returns if loader classes should be included to make the archive executable.
 	 * @return if the layout is executable

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

@@ -160,6 +160,16 @@ public final class Layouts {
 			return "WEB-INF/classes/";
 		}
 
+		@Override
+		public String getClasspathIndexFileLocation() {
+			return "WEB-INF/classpath.idx";
+		}
+
+		@Override
+		public String getLayersIndexFileLocation() {
+			return "WEB-INF/layers.idx";
+		}
+
 		@Override
 		public boolean isExecutable() {
 			return true;

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

@@ -172,7 +172,7 @@ public abstract class Packager {
 		}
 		writer.writeManifest(buildManifest(sourceJar));
 		writeLoaderClasses(writer);
-		writer.writeEntries(sourceJar, getEntityTransformer(), writeableLibraries);
+		writer.writeEntries(sourceJar, getEntityTransformer(), writeableLibraries, writeableLibraries::containsEntry);
 		writeableLibraries.write(writer);
 		if (isLayered()) {
 			writeLayerIndex(writer);
@@ -190,7 +190,7 @@ public abstract class Packager {
 	}
 
 	private void writeLayerIndex(AbstractJarWriter writer) throws IOException {
-		String name = ((RepackagingLayout) this.layout).getLayersIndexFileLocation();
+		String name = this.layout.getLayersIndexFileLocation();
 		if (StringUtils.hasLength(name)) {
 			Layer layer = this.layers.getLayer(name);
 			this.layersIndex.add(layer, name);
@@ -318,17 +318,17 @@ public abstract class Packager {
 
 	private void addBootAttributes(Attributes attributes) {
 		attributes.putValue(BOOT_VERSION_ATTRIBUTE, getClass().getPackage().getImplementationVersion());
+		addBootAttributesForLayout(attributes);
+	}
+
+	private void addBootAttributesForLayout(Attributes attributes) {
 		Layout layout = getLayout();
 		if (layout instanceof RepackagingLayout) {
-			addBootBootAttributesForRepackagingLayout(attributes, (RepackagingLayout) layout);
+			attributes.putValue(BOOT_CLASSES_ATTRIBUTE, ((RepackagingLayout) layout).getRepackagedClassesLocation());
 		}
 		else {
-			addBootBootAttributesForPlainLayout(attributes);
+			attributes.putValue(BOOT_CLASSES_ATTRIBUTE, layout.getClassesLocation());
 		}
-	}
-
-	private void addBootBootAttributesForRepackagingLayout(Attributes attributes, RepackagingLayout layout) {
-		attributes.putValue(BOOT_CLASSES_ATTRIBUTE, layout.getRepackagedClassesLocation());
 		putIfHasLength(attributes, BOOT_LIB_ATTRIBUTE, getLayout().getLibraryLocation("", LibraryScope.COMPILE));
 		putIfHasLength(attributes, BOOT_CLASSPATH_INDEX_ATTRIBUTE, layout.getClasspathIndexFileLocation());
 		if (isLayered()) {
@@ -336,11 +336,6 @@ public abstract class Packager {
 		}
 	}
 
-	private void addBootBootAttributesForPlainLayout(Attributes attributes) {
-		attributes.putValue(BOOT_CLASSES_ATTRIBUTE, getLayout().getClassesLocation());
-		putIfHasLength(attributes, BOOT_LIB_ATTRIBUTE, getLayout().getLibraryLocation("", LibraryScope.COMPILE));
-	}
-
 	private void putIfHasLength(Attributes attributes, String name, String value) {
 		if (StringUtils.hasLength(value)) {
 			attributes.putValue(name, value);
@@ -348,7 +343,7 @@ public abstract class Packager {
 	}
 
 	private boolean isLayered() {
-		return this.layers != null && getLayout() instanceof Layouts.Jar;
+		return this.layers != null;
 	}
 
 	/**
@@ -466,6 +461,10 @@ public abstract class Packager {
 			return Digest.sha1(library::openStream);
 		}
 
+		boolean containsEntry(String name) {
+			return this.libraries.containsKey(name);
+		}
+
 		private void write(AbstractJarWriter writer) throws IOException {
 			for (Entry<String, Library> entry : this.libraries.entrySet()) {
 				String path = entry.getKey();
@@ -473,12 +472,12 @@ public abstract class Packager {
 				String location = path.substring(0, path.lastIndexOf('/') + 1);
 				writer.writeNestedLibrary(location, library);
 			}
-			if (getLayout() instanceof RepackagingLayout) {
-				writeClasspathIndex((RepackagingLayout) getLayout(), writer);
+			if (Packager.this.layout instanceof RepackagingLayout) {
+				writeClasspathIndex(getLayout(), writer);
 			}
 		}
 
-		private void writeClasspathIndex(RepackagingLayout layout, AbstractJarWriter writer) throws IOException {
+		private void writeClasspathIndex(Layout layout, AbstractJarWriter writer) throws IOException {
 			List<String> names = this.libraries.keySet().stream().map((path) -> "- \"" + path + "\"")
 					.collect(Collectors.toList());
 			writer.writeIndexFile(layout.getClasspathIndexFileLocation(), names);

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

 /*
- * Copyright 2012-2020 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.
@@ -31,26 +31,4 @@ public interface RepackagingLayout extends Layout {
 	 */
 	String getRepackagedClassesLocation();
 
-	/**
-	 * Returns the location of the classpath index file that should be written or
-	 * {@code null} if not index is required. The result should include the filename and
-	 * is relative to the root of the jar.
-	 * @return the classpath index file location
-	 * @since 2.3.0
-	 */
-	default String getClasspathIndexFileLocation() {
-		return null;
-	}
-
-	/**
-	 * Returns the location of the layer index file that should be written or {@code null}
-	 * if not index is required. The result should include the filename and is relative to
-	 * the root of the jar.
-	 * @return the layer index file location
-	 * @since 2.3.0
-	 */
-	default String getLayersIndexFileLocation() {
-		return null;
-	}
-
 }

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/AbstractArchiveIntegrationTests.java

 /*
- * Copyright 2012-2020 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.
@@ -16,15 +16,22 @@
 
 package org.springframework.boot.maven;
 
+import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
 import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.function.Consumer;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
 import java.util.jar.Manifest;
 import java.util.stream.Stream;
+import java.util.zip.ZipEntry;
 
 import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.AssertProvider;
@@ -60,6 +67,33 @@ abstract class AbstractArchiveIntegrationTests {
 		};
 	}
 
+	protected Map<String, List<String>> readLayerIndex(JarFile jarFile) throws IOException {
+		if (getLayersIndexLocation() == null) {
+			return Collections.emptyMap();
+		}
+		Map<String, List<String>> index = new LinkedHashMap<>();
+		ZipEntry indexEntry = jarFile.getEntry(getLayersIndexLocation());
+		try (BufferedReader reader = new BufferedReader(new InputStreamReader(jarFile.getInputStream(indexEntry)))) {
+			String line = reader.readLine();
+			String layer = null;
+			while (line != null) {
+				if (line.startsWith("- ")) {
+					layer = line.substring(3, line.length() - 2);
+					index.put(layer, new ArrayList<>());
+				}
+				else if (line.startsWith("  - ")) {
+					index.computeIfAbsent(layer, (key) -> new ArrayList<>()).add(line.substring(5, line.length() - 1));
+				}
+				line = reader.readLine();
+			}
+			return index;
+		}
+	}
+
+	protected String getLayersIndexLocation() {
+		return null;
+	}
+
 	static final class JarAssert extends AbstractAssert<JarAssert, File> {
 
 		private JarAssert(File actual) {

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/JarIntegrationTests.java

 /*
- * Copyright 2012-2020 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.
@@ -16,18 +16,13 @@
 
 package org.springframework.boot.maven;
 
-import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
-import java.io.InputStreamReader;
-import java.util.ArrayList;
-import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.jar.JarFile;
 import java.util.stream.Collectors;
-import java.util.zip.ZipEntry;
 
 import org.junit.jupiter.api.TestTemplate;
 import org.junit.jupiter.api.extension.ExtendWith;
@@ -47,6 +42,11 @@ import static org.assertj.core.api.Assertions.assertThat;
 @ExtendWith(MavenBuildExtension.class)
 class JarIntegrationTests extends AbstractArchiveIntegrationTests {
 
+	@Override
+	protected String getLayersIndexLocation() {
+		return "BOOT-INF/layers.idx";
+	}
+
 	@TestTemplate
 	void whenJarIsRepackagedInPlaceOnlyRepackagedJarIsInstalled(MavenBuild mavenBuild) {
 		mavenBuild.project("jar").goals("install").execute((project) -> {
@@ -394,24 +394,4 @@ class JarIntegrationTests extends AbstractArchiveIntegrationTests {
 		return jarHash.get();
 	}
 
-	private Map<String, List<String>> readLayerIndex(JarFile jarFile) throws IOException {
-		Map<String, List<String>> index = new LinkedHashMap<>();
-		ZipEntry indexEntry = jarFile.getEntry("BOOT-INF/layers.idx");
-		try (BufferedReader reader = new BufferedReader(new InputStreamReader(jarFile.getInputStream(indexEntry)))) {
-			String line = reader.readLine();
-			String layer = null;
-			while (line != null) {
-				if (line.startsWith("- ")) {
-					layer = line.substring(3, line.length() - 2);
-					index.put(layer, new ArrayList<>());
-				}
-				else if (line.startsWith("  - ")) {
-					index.computeIfAbsent(layer, (key) -> new ArrayList<>()).add(line.substring(5, line.length() - 1));
-				}
-				line = reader.readLine();
-			}
-			return index;
-		}
-	}
-
 }

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/WarIntegrationTests.java

 /*
- * Copyright 2012-2020 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.
@@ -18,10 +18,15 @@ package org.springframework.boot.maven;
 
 import java.io.File;
 import java.io.FileReader;
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarFile;
 
 import org.junit.jupiter.api.TestTemplate;
 import org.junit.jupiter.api.extension.ExtendWith;
 
+import org.springframework.boot.loader.tools.JarModeLibrary;
 import org.springframework.util.FileCopyUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -34,6 +39,11 @@ import static org.assertj.core.api.Assertions.assertThat;
 @ExtendWith(MavenBuildExtension.class)
 class WarIntegrationTests extends AbstractArchiveIntegrationTests {
 
+	@Override
+	protected String getLayersIndexLocation() {
+		return "WEB-INF/layers.idx";
+	}
+
 	@TestTemplate
 	void warRepackaging(MavenBuild mavenBuild) {
 		mavenBuild.project("war")
@@ -89,4 +99,72 @@ class WarIntegrationTests extends AbstractArchiveIntegrationTests {
 		});
 	}
 
+	@TestTemplate
+	void repackagedWarContainsTheLayersIndexByDefault(MavenBuild mavenBuild) {
+		mavenBuild.project("war-layered").execute((project) -> {
+			File repackaged = new File(project, "war/target/war-layered-0.0.1.BUILD-SNAPSHOT.war");
+			assertThat(jar(repackaged)).hasEntryWithNameStartingWith("WEB-INF/classes/")
+					.hasEntryWithNameStartingWith("WEB-INF/lib/jar-release")
+					.hasEntryWithNameStartingWith("WEB-INF/lib/jar-snapshot").hasEntryWithNameStartingWith(
+							"WEB-INF/lib/" + JarModeLibrary.LAYER_TOOLS.getCoordinates().getArtifactId());
+			try (JarFile jarFile = new JarFile(repackaged)) {
+				Map<String, List<String>> layerIndex = readLayerIndex(jarFile);
+				assertThat(layerIndex.keySet()).containsExactly("dependencies", "spring-boot-loader",
+						"snapshot-dependencies", "application");
+				assertThat(layerIndex.get("application")).contains("WEB-INF/lib/jar-release-0.0.1.RELEASE.jar",
+						"WEB-INF/lib/jar-snapshot-0.0.1.BUILD-SNAPSHOT.jar");
+				assertThat(layerIndex.get("dependencies"))
+						.anyMatch((dependency) -> dependency.startsWith("WEB-INF/lib/spring-context"));
+				assertThat(layerIndex.get("dependencies"))
+						.anyMatch((dependency) -> dependency.startsWith("WEB-INF/lib-provided/"));
+			}
+			catch (IOException ex) {
+			}
+		});
+	}
+
+	@TestTemplate
+	void whenWarIsRepackagedWithTheLayersDisabledDoesNotContainLayersIndex(MavenBuild mavenBuild) {
+		mavenBuild.project("war-layered-disabled").execute((project) -> {
+			File repackaged = new File(project, "war/target/war-layered-0.0.1.BUILD-SNAPSHOT.war");
+			assertThat(jar(repackaged)).hasEntryWithNameStartingWith("WEB-INF/classes/")
+					.hasEntryWithNameStartingWith("WEB-INF/lib/jar-release")
+					.hasEntryWithNameStartingWith("WEB-INF/lib/jar-snapshot")
+					.doesNotHaveEntryWithName("WEB-INF/layers.idx")
+					.doesNotHaveEntryWithNameStartingWith("WEB-INF/lib/" + JarModeLibrary.LAYER_TOOLS.getName());
+		});
+	}
+
+	@TestTemplate
+	void whenWarIsRepackagedWithTheLayersEnabledAndLayerToolsExcluded(MavenBuild mavenBuild) {
+		mavenBuild.project("war-layered-no-layer-tools").execute((project) -> {
+			File repackaged = new File(project, "war/target/war-layered-0.0.1.BUILD-SNAPSHOT.war");
+			assertThat(jar(repackaged)).hasEntryWithNameStartingWith("WEB-INF/classes/")
+					.hasEntryWithNameStartingWith("WEB-INF/lib/jar-release")
+					.hasEntryWithNameStartingWith("WEB-INF/lib/jar-snapshot")
+					.hasEntryWithNameStartingWith("WEB-INF/layers.idx")
+					.doesNotHaveEntryWithNameStartingWith("WEB-INF/lib/" + JarModeLibrary.LAYER_TOOLS.getName());
+		});
+	}
+
+	@TestTemplate
+	void whenWarIsRepackagedWithTheCustomLayers(MavenBuild mavenBuild) {
+		mavenBuild.project("war-layered-custom").execute((project) -> {
+			File repackaged = new File(project, "war/target/war-layered-0.0.1.BUILD-SNAPSHOT.war");
+			assertThat(jar(repackaged)).hasEntryWithNameStartingWith("WEB-INF/classes/")
+					.hasEntryWithNameStartingWith("WEB-INF/lib/jar-release")
+					.hasEntryWithNameStartingWith("WEB-INF/lib/jar-snapshot");
+			try (JarFile jarFile = new JarFile(repackaged)) {
+				Map<String, List<String>> layerIndex = readLayerIndex(jarFile);
+				assertThat(layerIndex.keySet()).containsExactly("my-dependencies-name", "snapshot-dependencies",
+						"configuration", "application");
+				assertThat(layerIndex.get("application"))
+						.contains("WEB-INF/lib/jar-release-0.0.1.RELEASE.jar",
+								"WEB-INF/lib/jar-snapshot-0.0.1.BUILD-SNAPSHOT.jar",
+								"WEB-INF/lib/jar-classifier-0.0.1-bravo.jar")
+						.doesNotContain("WEB-INF/lib/jar-classifier-0.0.1-alpha.jar");
+			}
+		});
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-custom/jar-classifier/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-classifier</artifactId>
+	<version>0.0.1</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Classifier Jar dependency</description>
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-jar-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>alpha</id>
+						<phase>package</phase>
+						<goals>
+							<goal>jar</goal>
+						</goals>
+						<configuration>
+							<classifier>alpha</classifier>
+						</configuration>
+					</execution>
+                    <execution>
+                        <id>bravo</id>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>jar</goal>
+                        </goals>
+                        <configuration>
+                            <classifier>bravo</classifier>
+                        </configuration>
+                    </execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-custom/jar-release/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-release</artifactId>
+	<version>0.0.1.RELEASE</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Release Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-custom/jar-snapshot/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-snapshot</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Snapshot Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-custom/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>aggregator</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>pom</packaging>
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.source>@java.version@</maven.compiler.source>
+		<maven.compiler.target>@java.version@</maven.compiler.target>
+	</properties>
+	<modules>
+		<module>jar-classifier</module>
+		<module>jar-release</module>
+		<module>jar-snapshot</module>
+		<module>war</module>
+	</modules>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-custom/war/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot.maven.it</groupId>
+		<artifactId>aggregator</artifactId>
+		<version>0.0.1.BUILD-SNAPSHOT</version>
+	</parent>
+	<artifactId>war-layered</artifactId>
+	<packaging>war</packaging>
+	<name>war</name>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>@project.groupId@</groupId>
+				<artifactId>@project.artifactId@</artifactId>
+				<version>@project.version@</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>repackage</goal>
+						</goals>
+						<configuration>
+							<layers>
+								<enabled>true</enabled>
+								<configuration>${project.basedir}/src/layers.xml</configuration>
+							</layers>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-war-plugin</artifactId>
+				<version>@maven-war-plugin.version@</version>
+				<configuration>
+					<archive>
+						<manifestEntries>
+							<Not-Used>Foo</Not-Used>
+						</manifestEntries>
+					</archive>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-context</artifactId>
+			<version>@spring-framework.version@</version>
+		</dependency>
+		<dependency>
+			<groupId>jakarta.servlet</groupId>
+			<artifactId>jakarta.servlet-api</artifactId>
+			<version>@jakarta-servlet.version@</version>
+			<scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-snapshot</artifactId>
+			<version>0.0.1.BUILD-SNAPSHOT</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-classifier</artifactId>
+			<version>0.0.1</version>
+			<classifier>bravo</classifier>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-release</artifactId>
+			<version>0.0.1.RELEASE</version>
+		</dependency>
+	</dependencies>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-custom/war/src/layers.xml

+<layers xmlns="http://www.springframework.org/schema/boot/layers"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/boot/layers
+					  https://www.springframework.org/schema/layers/layers-2.4.xsd">
+	<application>
+		<into layer="configuration">
+			<include>**/application*.*</include>
+		</into>
+		<into layer="application" />
+	</application>
+	<dependencies>
+		<into layer="application">
+			<includeModuleDependencies />
+		</into>
+		<into layer="snapshot-dependencies">
+			<include>*:*:*-SNAPSHOT</include>
+		</into>
+		<into layer="my-dependencies-name" />
+	</dependencies>
+	<layerOrder>
+		<layer>my-dependencies-name</layer>
+		<layer>snapshot-dependencies</layer>
+		<layer>configuration</layer>
+		<layer>application</layer>
+	</layerOrder>
+</layers>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-custom/war/src/main/java/org/test/SampleApplication.java

+/*
+ * Copyright 2012-2020 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.test;
+
+public class SampleApplication {
+
+	public static void main(String[] args) {
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-custom/war/src/main/webapp/index.html

+<html></html>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-disabled/jar-release/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-release</artifactId>
+	<version>0.0.1.RELEASE</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Release Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-disabled/jar-snapshot/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-snapshot</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Snapshot Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-disabled/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>aggregator</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>pom</packaging>
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.source>@java.version@</maven.compiler.source>
+		<maven.compiler.target>@java.version@</maven.compiler.target>
+	</properties>
+	<modules>
+		<module>jar-snapshot</module>
+		<module>jar-release</module>
+		<module>war</module>
+	</modules>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-disabled/war/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot.maven.it</groupId>
+		<artifactId>aggregator</artifactId>
+		<version>0.0.1.BUILD-SNAPSHOT</version>
+	</parent>
+	<artifactId>war-layered</artifactId>
+	<packaging>war</packaging>
+	<name>war</name>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>@project.groupId@</groupId>
+				<artifactId>@project.artifactId@</artifactId>
+				<version>@project.version@</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>repackage</goal>
+						</goals>
+						<configuration>
+							<layers>
+								<enabled>false</enabled>
+							</layers>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-war-plugin</artifactId>
+				<version>@maven-war-plugin.version@</version>
+				<configuration>
+					<archive>
+						<manifestEntries>
+							<Not-Used>Foo</Not-Used>
+						</manifestEntries>
+					</archive>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-context</artifactId>
+			<version>@spring-framework.version@</version>
+		</dependency>
+		<dependency>
+			<groupId>jakarta.servlet</groupId>
+			<artifactId>jakarta.servlet-api</artifactId>
+			<version>@jakarta-servlet.version@</version>
+			<scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-snapshot</artifactId>
+			<version>0.0.1.BUILD-SNAPSHOT</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-release</artifactId>
+			<version>0.0.1.RELEASE</version>
+		</dependency>
+	</dependencies>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-disabled/war/src/main/java/org/test/SampleApplication.java

+/*
+ * Copyright 2012-2020 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.test;
+
+public class SampleApplication {
+
+	public static void main(String[] args) {
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-disabled/war/src/main/webapp/index.html

+<html></html>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-no-layer-tools/jar-release/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-release</artifactId>
+	<version>0.0.1.RELEASE</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Release Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-no-layer-tools/jar-snapshot/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-snapshot</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Snapshot Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-no-layer-tools/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>aggregator</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>pom</packaging>
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.source>@java.version@</maven.compiler.source>
+		<maven.compiler.target>@java.version@</maven.compiler.target>
+	</properties>
+	<modules>
+		<module>jar-snapshot</module>
+		<module>jar-release</module>
+		<module>war</module>
+	</modules>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-no-layer-tools/war/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot.maven.it</groupId>
+		<artifactId>aggregator</artifactId>
+		<version>0.0.1.BUILD-SNAPSHOT</version>
+	</parent>
+	<artifactId>war-layered</artifactId>
+	<packaging>war</packaging>
+	<name>war</name>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>@project.groupId@</groupId>
+				<artifactId>@project.artifactId@</artifactId>
+				<version>@project.version@</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>repackage</goal>
+						</goals>
+						<configuration>
+							<layers>
+								<includeLayerTools>false</includeLayerTools>
+							</layers>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-war-plugin</artifactId>
+				<version>@maven-war-plugin.version@</version>
+				<configuration>
+					<archive>
+						<manifestEntries>
+							<Not-Used>Foo</Not-Used>
+						</manifestEntries>
+					</archive>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-context</artifactId>
+			<version>@spring-framework.version@</version>
+		</dependency>
+		<dependency>
+			<groupId>jakarta.servlet</groupId>
+			<artifactId>jakarta.servlet-api</artifactId>
+			<version>@jakarta-servlet.version@</version>
+			<scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-snapshot</artifactId>
+			<version>0.0.1.BUILD-SNAPSHOT</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-release</artifactId>
+			<version>0.0.1.RELEASE</version>
+		</dependency>
+	</dependencies>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-no-layer-tools/war/src/main/java/org/test/SampleApplication.java

+/*
+ * Copyright 2012-2020 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.test;
+
+public class SampleApplication {
+
+	public static void main(String[] args) {
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered-no-layer-tools/war/src/main/webapp/index.html

+<html></html>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered/jar-release/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-release</artifactId>
+	<version>0.0.1.RELEASE</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Release Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered/jar-snapshot/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-snapshot</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Snapshot Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>aggregator</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>pom</packaging>
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.source>@java.version@</maven.compiler.source>
+		<maven.compiler.target>@java.version@</maven.compiler.target>
+	</properties>
+	<modules>
+		<module>jar-snapshot</module>
+		<module>jar-release</module>
+		<module>war</module>
+	</modules>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered/war/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot.maven.it</groupId>
+		<artifactId>aggregator</artifactId>
+		<version>0.0.1.BUILD-SNAPSHOT</version>
+	</parent>
+	<artifactId>war-layered</artifactId>
+	<packaging>war</packaging>
+	<name>war</name>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>@project.groupId@</groupId>
+				<artifactId>@project.artifactId@</artifactId>
+				<version>@project.version@</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>repackage</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-war-plugin</artifactId>
+				<version>@maven-war-plugin.version@</version>
+				<configuration>
+					<archive>
+						<manifestEntries>
+							<Not-Used>Foo</Not-Used>
+						</manifestEntries>
+					</archive>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-context</artifactId>
+			<version>@spring-framework.version@</version>
+		</dependency>
+		<dependency>
+			<groupId>jakarta.servlet</groupId>
+			<artifactId>jakarta.servlet-api</artifactId>
+			<version>@jakarta-servlet.version@</version>
+			<scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-snapshot</artifactId>
+			<version>0.0.1.BUILD-SNAPSHOT</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-release</artifactId>
+			<version>0.0.1.RELEASE</version>
+		</dependency>
+	</dependencies>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered/war/src/main/java/org/test/SampleApplication.java

+/*
+ * Copyright 2012-2020 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.test;
+
+public class SampleApplication {
+
+	public static void main(String[] args) {
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/war-layered/war/src/main/webapp/index.html

+<html></html>

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

@@ -182,7 +182,10 @@ public abstract class AbstractPackagerMojo extends AbstractDependencyFilterMojo
 	 * @throws MojoExecutionException on execution error
 	 */
 	protected final Libraries getLibraries(Collection<Dependency> unpacks) throws MojoExecutionException {
-		Set<Artifact> artifacts = filterDependencies(this.project.getArtifacts(), getFilters(getAdditionalFilters()));
+		String packaging = this.project.getPackaging();
+		Set<Artifact> projectArtifacts = this.project.getArtifacts();
+		Set<Artifact> artifacts = ("war".equals(packaging)) ? projectArtifacts
+				: filterDependencies(projectArtifacts, getFilters(getAdditionalFilters()));
 		return new ArtifactsLibraries(artifacts, this.session.getProjects(), unpacks, getLog());
 	}