Combine application and resources layers into a single layer

Closes gh-20562

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

@@ -284,11 +284,10 @@ By default, the following layers are created:
 
 * `dependencies` for any dependency whose version does not contain `SNAPSHOT`.
 * `snapshot-dependencies` for any dependency whose version contains `SNAPSHOT`.
-* `resources` for static resources at the default locations, i.e. `META-INF/resources/`, `resources/`, `static/`, `public/`.
+* `application` for application classes and resources.
-* `application` for any other classes and resources.
 
 The layers order is important as it determines how likely previous layers can be cached when part of the application changes.
-The default order is `dependencies`, `snapshot-dependencies`, `resources`, and `application`.
+The default order is `dependencies`, `snapshot-dependencies`, and `application`.
 Content that is least likely to change should be added first, followed by layers that are more likely to change.
 
 When you create a layered jar, the `spring-boot-layertools` jar will be added as a dependency to your jar.
@@ -328,7 +327,7 @@ include::../gradle/packaging/boot-jar-layered-custom.gradle.kts[tags=layered]
 
 Each `layerContent` closure defines a strategy to include or exclude an entry of the jar in a layer.
 When an entry matches a strategy, it is included in the layer and further strategies are ignored.
-This is illustrated by the `dependencies` and `application` layers that have a "catch-all" include filter used to add any libraries or classes that were not processed by previous strategies.
+This is illustrated by the `dependencies` layer that has a "catch-all" include filter used to add any libraries that were not processed by previous strategies.
 
 The content of a `libraries` layer can be customized using filters to `include` or `exclude` based on the dependency coordinates.
 The format is `groupId:artifactId[:version]`.

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/packaging/boot-jar-layered-custom.gradle

@@ -10,7 +10,7 @@ bootJar {
 // tag::layered[]
 bootJar {
 	layers {
-		layersOrder "dependencies", "snapshot-dependencies", "resources", "application"
+		layersOrder "dependencies", "snapshot-dependencies", "application"
 		libraries {
 			layerContent("snapshot-dependencies") {
 				coordinates {
@@ -24,12 +24,6 @@ bootJar {
 			}
 		}
 		application {
-			layerContent("resources") {
-				locations {
-					include "META-INF/resources/**", "resources/**"
-					include "static/**", "public/**"
-				}
-			}
 			layerContent("application") {
 				locations {
 					include "**"

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/packaging/boot-jar-layered-custom.gradle.kts

@@ -8,7 +8,7 @@ plugins {
 // tag::layered[]
 tasks.getByName<BootJar>("bootJar") {
 	layers {
-		layersOrder("dependencies", "snapshot-dependencies", "resources", "application")
+		layersOrder("dependencies", "snapshot-dependencies", "application")
 		libraries {
 			layerContent("snapshot-dependencies") {
 				coordinates {
@@ -22,12 +22,6 @@ tasks.getByName<BootJar>("bootJar") {
 			}
 		}
 		application {
-			layerContent("resources") {
-				locations {
-					include("META-INF/resources/**", "resources/**")
-					include("static/**", "public/**")
-				}
-			}
 			layerContent("application") {
 				locations {
 					include("**")

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootJarIntegrationTests.java

@@ -81,7 +81,7 @@ class BootJarIntegrationTests extends AbstractBootArchiveIntegrationTests {
 			assertThat(jarFile.getEntry("BOOT-INF/layers/snapshot-dependencies/lib/commons-io-2.7-SNAPSHOT.jar"))
 					.isNotNull();
 			assertThat(jarFile.getEntry("BOOT-INF/layers/application/classes/example/Main.class")).isNotNull();
-			assertThat(jarFile.getEntry("BOOT-INF/layers/resources/classes/static/file.txt")).isNotNull();
+			assertThat(jarFile.getEntry("BOOT-INF/layers/application/classes/static/file.txt")).isNotNull();
 		}
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootJarTests.java

@@ -103,7 +103,7 @@ class BootJarTests extends AbstractBootArchiveTests<BootJar> {
 	void whenJarIsLayeredThenLayersIndexIsPresentAndListsLayersInOrder() throws IOException {
 		try (JarFile jarFile = new JarFile(createLayeredJar())) {
 			assertThat(entryLines(jarFile, "BOOT-INF/layers.idx")).containsExactly("dependencies",
-					"snapshot-dependencies", "resources", "application");
+					"snapshot-dependencies", "application");
 		}
 	}
 
@@ -116,7 +116,7 @@ class BootJarTests extends AbstractBootArchiveTests<BootJar> {
 				.contains("BOOT-INF/layers/snapshot-dependencies/lib/third-library-SNAPSHOT.jar")
 				.containsSubsequence("BOOT-INF/layers/application/classes/com/example/Application.class",
 						"BOOT-INF/layers/application/classes/application.properties")
-				.contains("BOOT-INF/layers/resources/classes/static/test.css");
+				.contains("BOOT-INF/layers/application/classes/static/test.css");
 	}
 
 	@Test

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

@@ -24,13 +24,8 @@ package org.springframework.boot.loader.tools;
  */
 class ImplicitLayerResolver extends StandardLayers {
 
-	private static final String[] RESOURCE_LOCATIONS = { "META-INF/resources/", "resources/", "static/", "public/" };
-
 	@Override
 	public Layer getLayer(String name) {
-		if (!isClassFile(name) && isInResourceLocation(name)) {
-			return RESOURCES;
-		}
 		return APPLICATION;
 	}
 
@@ -42,17 +37,4 @@ class ImplicitLayerResolver extends StandardLayers {
 		return DEPENDENCIES;
 	}
 
-	private boolean isClassFile(String name) {
-		return name.endsWith(".class");
-	}
-
-	private boolean isInResourceLocation(String name) {
-		for (String resourceLocation : RESOURCE_LOCATIONS) {
-			if (name.startsWith(resourceLocation)) {
-				return true;
-			}
-		}
-		return false;
-	}
-
 }

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

@@ -26,7 +26,6 @@ import java.util.List;
  * <ol>
  * <li>"dependencies" - For non snapshot dependencies</li>
  * <li>"snapshot-dependencies" - For snapshot dependencies</li>
- * <li>"resources" - For static resources such as HTML files</li>
  * <li>"application" - For application classes and resources</li>
  * </ol>
  *
@@ -46,11 +45,6 @@ public abstract class StandardLayers implements Layers {
 	 */
 	public static final Layer SNAPSHOT_DEPENDENCIES = new Layer("snapshot-dependencies");
 
-	/**
-	 * The resources layer.
-	 */
-	public static final Layer RESOURCES = new Layer("resources");
-
 	/**
 	 * The application layer.
 	 */
@@ -61,7 +55,6 @@ public abstract class StandardLayers implements Layers {
 		List<Layer> layers = new ArrayList<>();
 		layers.add(DEPENDENCIES);
 		layers.add(SNAPSHOT_DEPENDENCIES);
-		layers.add(RESOURCES);
 		layers.add(APPLICATION);
 		LAYERS = Collections.unmodifiableList(layers);
 	}

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

@@ -35,15 +35,15 @@ class ImplicitLayerResolverTests {
 	@Test
 	void iteratorReturnsLayers() {
 		assertThat(this.layers).containsExactly(StandardLayers.DEPENDENCIES, StandardLayers.SNAPSHOT_DEPENDENCIES,
-				StandardLayers.RESOURCES, StandardLayers.APPLICATION);
+				StandardLayers.APPLICATION);
 	}
 
 	@Test
-	void getLayerWhenNameInResourceLocationReturnsResourceLayer() {
+	void getLayerWhenNameInResourceLocationReturnsApplicationLayer() {
-		assertThat(this.layers.getLayer("META-INF/resources/logo.gif")).isEqualTo(StandardLayers.RESOURCES);
+		assertThat(this.layers.getLayer("META-INF/resources/logo.gif")).isEqualTo(StandardLayers.APPLICATION);
-		assertThat(this.layers.getLayer("resources/logo.gif")).isEqualTo(StandardLayers.RESOURCES);
+		assertThat(this.layers.getLayer("resources/logo.gif")).isEqualTo(StandardLayers.APPLICATION);
-		assertThat(this.layers.getLayer("static/logo.gif")).isEqualTo(StandardLayers.RESOURCES);
+		assertThat(this.layers.getLayer("static/logo.gif")).isEqualTo(StandardLayers.APPLICATION);
-		assertThat(this.layers.getLayer("public/logo.gif")).isEqualTo(StandardLayers.RESOURCES);
+		assertThat(this.layers.getLayer("public/logo.gif")).isEqualTo(StandardLayers.APPLICATION);
 	}
 
 	@Test

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

@@ -102,11 +102,10 @@ By default, the following layers are created:
 
 * `dependencies` for any dependency whose version does not contain `SNAPSHOT`.
 * `snapshot-dependencies` for any dependency whose version contains `SNAPSHOT`.
-* `resources` for static resources at the default locations, i.e. `META-INF/resources/`, `resources/`, `static/`, `public/`.
+* `application` for application classes and resources.
-* `application` for any other classes and resources.
 
 The layers order is important as it determines how likely previous layers can be cached when part of the application changes.
-The default order is `dependencies`, `snapshot-dependencies`, `resources`, and `application`.
+The default order is `dependencies`, `snapshot-dependencies`, and `application`.
 Content that is least likely to change should be added first, followed by layers that are more likely to change.
 
 
@@ -149,7 +148,6 @@ The following example shows what the implicit layer configuration described abov
 	<layers>
 		<layer>dependencies</layer>
 		<layer>snapshot-dependencies</layer>
-		<layer>resources</layer>
 		<layer>application</layer>
     </layers>
 	<libraries>
@@ -165,14 +163,6 @@ The following example shows what the implicit layer configuration described abov
 		</layer-content>
 	</libraries>
 	<application>
-		<layer-content layer="resources">
-			<locations>
-				<include>META-INF/resources/**</include>
-				<include>resources/**</include>
-				<include>static/**</include>
-				<include>public/**</include>
-			</locations>
-		</layer-content>
 		<layer-content layer="application">
 			<locations>
 				<include>**</include>
@@ -184,7 +174,7 @@ The following example shows what the implicit layer configuration described abov
 
 Each `layer-content` element defines a strategy to include or exclude an entry of the jar in a layer.
 When an entry matches a strategy, it is included in the layer and further strategies are ignored.
-This is illustrated by the `dependencies` and `application` layers that have a "catch-all" include filter used to add any libraries or classes that were not processed by previous strategies.
+This is illustrated by the `dependencies` layer that has a "catch-all" include filter used to add any libraries that were not processed by previous strategies.
 
 The content of a `libraries` layer can be customized using filters to `include` or `exclude` based on the dependency coordinates.
 The format is `groupId:artifactId[:version]`.