Add exception and failure analyzer for missing AOT initializer

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/AotInitializerNotFoundException.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2012-2024 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.springframework.boot;
+
+/**
+ * Thrown when the AOT initializer couldn't be found.
+ * @author Moritz Halbritter
+ */
+class AotInitializerNotFoundException extends RuntimeException {
+	private final Class<?> mainClass;
+
+	private final String initializerClassName;
+
+	AotInitializerNotFoundException(Class<?> mainClass, String initializerClassName) {
+		this.mainClass = mainClass;
+		this.initializerClassName = initializerClassName;
+	}
+
+	Class<?> getMainClass() {
+		return this.mainClass;
+	}
+
+	String getInitializerClassName() {
+		return this.initializerClassName;
+	}
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/AotInitializerNotFoundFailureAnalyzer.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2012-2024 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.springframework.boot;
+
+import org.springframework.boot.diagnostics.AbstractFailureAnalyzer;
+import org.springframework.boot.diagnostics.FailureAnalysis;
+
+/**
+ * An {@link AbstractFailureAnalyzer} that performs analysis of failures caused by a
+ * {@link AotInitializerNotFoundException}.
+ *
+ * @author Moritz Halbritter
+ */
+class AotInitializerNotFoundFailureAnalyzer extends AbstractFailureAnalyzer<AotInitializerNotFoundException> {
+	@Override
+	protected FailureAnalysis analyze(Throwable rootFailure, AotInitializerNotFoundException cause) {
+		return new FailureAnalysis("Startup with AOT mode enabled failed: AOT initializer %s could not be found".formatted(cause.getInitializerClassName()),
+				"Consider the following:\n"
+						+ "\tDid you build the application with enabled AOT processing?\n"
+						+ "\tIs the main class %s correct?\n".formatted(cause.getMainClass().getName())
+						+ "\tIf you want to run the application in regular mode, remove the system property 'spring.aot.enabled'",
+				cause);
+	}
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

@@ -439,10 +439,9 @@ private void addAotGeneratedInitializerIfNecessary(List<ApplicationContextInitia
 					initializers.stream().filter(AotApplicationContextInitializer.class::isInstance).toList());
 			if (aotInitializers.isEmpty()) {
 				String initializerClassName = this.mainApplicationClass.getName() + "__ApplicationContextInitializer";
-				Assert.state(ClassUtils.isPresent(initializerClassName, getClassLoader()),
-						"You are starting the application with AOT mode enabled but AOT processing hasn't happened. "
-								+ "Please build your application with enabled AOT processing first, "
-								+ "or remove the system property 'spring.aot.enabled' to run the application in regular mode");
+				if (!ClassUtils.isPresent(initializerClassName, getClassLoader())) {
+					throw new AotInitializerNotFoundException(this.mainApplicationClass, initializerClassName);
+				}
 				aotInitializers.add(AotApplicationContextInitializer.forInitializerClasses(initializerClassName));
 			}
 			initializers.removeAll(aotInitializers);

spring-boot-project/spring-boot/src/main/resources/META-INF/spring.factories

@@ -61,6 +61,7 @@ org.springframework.boot.reactor.ReactorEnvironmentPostProcessor
 
 # Failure Analyzers
 org.springframework.boot.diagnostics.FailureAnalyzer=\
+org.springframework.boot.AotInitializerNotFoundFailureAnalyzer,\
 org.springframework.boot.context.config.ConfigDataNotFoundFailureAnalyzer,\
 org.springframework.boot.context.properties.IncompatibleConfigurationFailureAnalyzer,\
 org.springframework.boot.context.properties.NotConstructorBoundInjectionFailureAnalyzer,\