Drop spring-boot-loader-classic support

Closes gh-45714

Author: philwebb

build-plugin/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/BootArchive.java

@@ -34,8 +34,6 @@
 import org.gradle.api.tasks.Optional;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.loader.tools.LoaderImplementation;
-
 /**
  * A Spring Boot "fat" archive task.
  *
@@ -137,15 +135,6 @@ public interface BootArchive extends Task {
 	 */
 	void resolvedArtifacts(Provider<Set<ResolvedArtifactResult>> resolvedArtifacts);
 
-	/**
-	 * The loader implementation that should be used with the archive.
-	 * @return the loader implementation
-	 * @since 3.2.0
-	 */
-	@Input
-	@Optional
-	Property<LoaderImplementation> getLoaderImplementation();
-
 	/**
 	 * Returns whether the JAR tools should be included as a dependency in the layered
 	 * archive.

build-plugin/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/BootArchiveSupport.java

@@ -46,8 +46,6 @@
 import org.gradle.util.GradleVersion;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.loader.tools.LoaderImplementation;
-
 /**
  * Support class for implementations of {@link BootArchive}.
  *
@@ -123,13 +121,11 @@ private String determineSpringBootVersion() {
 		return (version != null) ? version : "unknown";
 	}
 
-	CopyAction createCopyAction(Jar jar, ResolvedDependencies resolvedDependencies,
-			LoaderImplementation loaderImplementation, boolean supportsSignatureFile) {
-		return createCopyAction(jar, resolvedDependencies, loaderImplementation, supportsSignatureFile, null, null);
+	CopyAction createCopyAction(Jar jar, ResolvedDependencies resolvedDependencies, boolean supportsSignatureFile) {
+		return createCopyAction(jar, resolvedDependencies, supportsSignatureFile, null, null);
 	}
 
-	CopyAction createCopyAction(Jar jar, ResolvedDependencies resolvedDependencies,
-			LoaderImplementation loaderImplementation, boolean supportsSignatureFile,
+	CopyAction createCopyAction(Jar jar, ResolvedDependencies resolvedDependencies, boolean supportsSignatureFile,
 			@Nullable LayerResolver layerResolver, @Nullable String jarmodeToolsLocation) {
 		File output = jar.getArchiveFile().get().getAsFile();
 		Manifest manifest = jar.getManifest();
@@ -145,8 +141,7 @@ CopyAction createCopyAction(Jar jar, ResolvedDependencies resolvedDependencies,
 		String encoding = jar.getMetadataCharset();
 		CopyAction action = new BootZipCopyAction(output, manifest, preserveFileTimestamps, dirPermissions,
 				filePermissions, includeDefaultLoader, jarmodeToolsLocation, requiresUnpack, exclusions, launchScript,
-				librarySpec, compressionResolver, encoding, resolvedDependencies, supportsSignatureFile, layerResolver,
-				loaderImplementation);
+				librarySpec, compressionResolver, encoding, resolvedDependencies, supportsSignatureFile, layerResolver);
 		return jar.isReproducibleFileOrder() ? new ReproducibleOrderingCopyAction(action) : action;
 	}
 

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

@@ -38,8 +38,6 @@
 import org.gradle.work.DisableCachingByDefault;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.loader.tools.LoaderImplementation;
-
 /**
  * A custom {@link Jar} task that produces a Spring Boot executable jar.
  *
@@ -145,13 +143,12 @@ private boolean isLayeredDisabled() {
 
 	@Override
 	protected CopyAction createCopyAction() {
-		LoaderImplementation loaderImplementation = getLoaderImplementation().getOrElse(LoaderImplementation.DEFAULT);
 		LayerResolver layerResolver = null;
 		if (!isLayeredDisabled()) {
 			layerResolver = new LayerResolver(this.resolvedDependencies, this.layered, this::isLibrary);
 		}
 		String jarmodeToolsLocation = isIncludeJarmodeTools() ? LIB_DIRECTORY : null;
-		return this.support.createCopyAction(this, this.resolvedDependencies, loaderImplementation, true, layerResolver,
+		return this.support.createCopyAction(this, this.resolvedDependencies, true, layerResolver,
 				jarmodeToolsLocation);
 	}
 

build-plugin/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/BootWar.java

@@ -38,8 +38,6 @@
 import org.gradle.work.DisableCachingByDefault;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.loader.tools.LoaderImplementation;
-
 /**
  * A custom {@link War} task that produces a Spring Boot executable war.
  *
@@ -119,14 +117,13 @@ private boolean isLayeredDisabled() {
 
 	@Override
 	protected CopyAction createCopyAction() {
-		LoaderImplementation loaderImplementation = getLoaderImplementation().getOrElse(LoaderImplementation.DEFAULT);
 		LayerResolver layerResolver = null;
 		if (!isLayeredDisabled()) {
 			layerResolver = new LayerResolver(this.resolvedDependencies, this.layered, this::isLibrary);
 		}
 		String jarmodeToolsLocation = isIncludeJarmodeTools() ? LIB_DIRECTORY : null;
-		return this.support.createCopyAction(this, this.resolvedDependencies, loaderImplementation, false,
-				layerResolver, jarmodeToolsLocation);
+		return this.support.createCopyAction(this, this.resolvedDependencies, false, layerResolver,
+				jarmodeToolsLocation);
 	}
 
 	private boolean isIncludeJarmodeTools() {

build-plugin/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/BootZipCopyAction.java

@@ -63,7 +63,6 @@
 import org.springframework.boot.loader.tools.Layer;
 import org.springframework.boot.loader.tools.LayersIndex;
 import org.springframework.boot.loader.tools.LibraryCoordinates;
-import org.springframework.boot.loader.tools.LoaderImplementation;
 import org.springframework.boot.loader.tools.NativeImageArgFile;
 import org.springframework.boot.loader.tools.ReachabilityMetadataProperties;
 import org.springframework.util.Assert;
@@ -120,15 +119,13 @@ class BootZipCopyAction implements CopyAction {
 
 	private final @Nullable LayerResolver layerResolver;
 
-	private final LoaderImplementation loaderImplementation;
-
 	BootZipCopyAction(File output, Manifest manifest, boolean preserveFileTimestamps, @Nullable Integer dirMode,
 			@Nullable Integer fileMode, boolean includeDefaultLoader, @Nullable String jarmodeToolsLocation,
 			Spec<FileTreeElement> requiresUnpack, Spec<FileTreeElement> exclusions,
 			@Nullable LaunchScriptConfiguration launchScript, Spec<FileCopyDetails> librarySpec,
 			Function<FileCopyDetails, ZipCompression> compressionResolver, @Nullable String encoding,
 			ResolvedDependencies resolvedDependencies, boolean supportsSignatureFile,
-			@Nullable LayerResolver layerResolver, LoaderImplementation loaderImplementation) {
+			@Nullable LayerResolver layerResolver) {
 		this.output = output;
 		this.manifest = manifest;
 		this.preserveFileTimestamps = preserveFileTimestamps;
@@ -145,7 +142,6 @@ class BootZipCopyAction implements CopyAction {
 		this.resolvedDependencies = resolvedDependencies;
 		this.supportsSignatureFile = supportsSignatureFile;
 		this.layerResolver = layerResolver;
-		this.loaderImplementation = loaderImplementation;
 	}
 
 	@Override
@@ -329,8 +325,7 @@ private void writeLoaderEntriesIfNecessary(@Nullable FileCopyDetails details) th
 				// Always write loader entries after META-INF directory (see gh-16698)
 				return;
 			}
-			LoaderZipEntries loaderEntries = new LoaderZipEntries(getTime(), getDirMode(), getFileMode(),
-					BootZipCopyAction.this.loaderImplementation);
+			LoaderZipEntries loaderEntries = new LoaderZipEntries(getTime(), getDirMode(), getFileMode());
 			this.writtenLoaderEntries = loaderEntries.writeTo(this.out);
 			if (BootZipCopyAction.this.layerResolver != null) {
 				for (String name : this.writtenLoaderEntries.getFiles()) {

build-plugin/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/tasks/bundling/LoaderZipEntries.java

@@ -29,7 +29,6 @@
 import org.gradle.api.file.FileTreeElement;
 import org.jspecify.annotations.Nullable;
 
-import org.springframework.boot.loader.tools.LoaderImplementation;
 import org.springframework.util.Assert;
 import org.springframework.util.StreamUtils;
 
@@ -42,27 +41,22 @@
  */
 class LoaderZipEntries {
 
-	private final LoaderImplementation loaderImplementation;
-
 	private final @Nullable Long entryTime;
 
 	private final int dirMode;
 
 	private final int fileMode;
 
-	LoaderZipEntries(@Nullable Long entryTime, int dirMode, int fileMode,
-			@Nullable LoaderImplementation loaderImplementation) {
+	LoaderZipEntries(@Nullable Long entryTime, int dirMode, int fileMode) {
 		this.entryTime = entryTime;
 		this.dirMode = dirMode;
 		this.fileMode = fileMode;
-		this.loaderImplementation = (loaderImplementation != null) ? loaderImplementation
-				: LoaderImplementation.DEFAULT;
 	}
 
 	WrittenEntries writeTo(ZipArchiveOutputStream out) throws IOException {
 		WrittenEntries written = new WrittenEntries();
 		try (ZipInputStream loaderJar = new ZipInputStream(
-				getResourceAsStream("/" + this.loaderImplementation.getJarResourceName()))) {
+				getResourceAsStream("/META-INF/loader/spring-boot-loader.jar"))) {
 			java.util.zip.ZipEntry entry = loaderJar.getNextEntry();
 			while (entry != null) {
 				if (entry.isDirectory() && !entry.getName().equals("META-INF/")) {

build-plugin/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/AbstractBootArchiveIntegrationTests.java

@@ -108,16 +108,6 @@ void reproducibleArchive() throws IOException, InterruptedException {
 		assertThat(firstHash).isEqualTo(secondHash);
 	}
 
-	@TestTemplate
-	void classicLoader() throws IOException {
-		assertThat(this.gradleBuild.build(this.taskName).task(":" + this.taskName).getOutcome())
-			.isEqualTo(TaskOutcome.SUCCESS);
-		File jar = new File(this.gradleBuild.getProjectDir(), "build/libs").listFiles()[0];
-		try (JarFile jarFile = new JarFile(jar)) {
-			assertThat(jarFile.getEntry("org/springframework/boot/loader/LaunchedURLClassLoader.class")).isNotNull();
-		}
-	}
-
 	@TestTemplate
 	void upToDateWhenBuiltTwice() {
 		assertThat(this.gradleBuild.build(this.taskName).task(":" + this.taskName).getOutcome())

build-plugin/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/AbstractBootArchiveTests.java

@@ -65,7 +65,6 @@
 import org.springframework.boot.gradle.junit.GradleProjectBuilder;
 import org.springframework.boot.loader.tools.DefaultLaunchScript;
 import org.springframework.boot.loader.tools.JarModeLibrary;
-import org.springframework.boot.loader.tools.LoaderImplementation;
 import org.springframework.util.FileCopyUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -283,17 +282,6 @@ void loaderIsWrittenToTheRootOfTheJarWhenUsingThePropertiesLauncher() throws IOE
 		}
 	}
 
-	@Test
-	void loaderIsWrittenToTheRootOfTheJarWhenUsingClassicLoader() throws IOException {
-		this.task.getMainClass().set("com.example.Main");
-		this.task.getLoaderImplementation().set(LoaderImplementation.CLASSIC);
-		executeTask();
-		try (JarFile jarFile = new JarFile(this.task.getArchiveFile().get().getAsFile())) {
-			assertThat(jarFile.getEntry("org/springframework/boot/loader/LaunchedURLClassLoader.class")).isNotNull();
-			assertThat(jarFile.getEntry("org/springframework/boot/loader/")).isNotNull();
-		}
-	}
-
 	@Test
 	void unpackCommentIsAddedToEntryIdentifiedByAPattern() throws IOException {
 		this.task.getMainClass().set("com.example.Main");