Spring AotInitializerNotFoundException with AOT

[andreaabram-eutelsat]

Dependencies:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
    <version>3.5.7</version>
</dependency>
<dependency>
    <groupId>com.amazonaws.serverless</groupId>
    <artifactId>aws-serverless-java-container-springboot3</artifactId>
    <version>2.1.5</version>
</dependency>

Handler

public class StreamLambdaHandler implements RequestStreamHandler {

    private static final Logger logger = LoggerFactory.getLogger(StreamLambdaHandler.class);

    private static SpringBootLambdaContainerHandler<AwsProxyRequest, AwsProxyResponse> handler;

    static {
        try {
            handler = SpringBootLambdaContainerHandler.getAwsProxyHandler(IssueApplication.class);
        } catch (ContainerInitializationException e) {
            // if we fail here. We re-throw the exception to force another cold start
            e.printStackTrace();
            throw new RuntimeException("Could not initialize Spring Boot application", e);
        }
    }

    @Override
    public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context)
        throws IOException {
        logger.info("entered generic stream lambda handler");
        handler.proxyStream(inputStream, outputStream, context);
    }
}

Issue

Description:

Startup with AOT mode enabled failed: AOT initializer com.amazonaws.services.lambda.runtime.api.client.AWSLambda__ApplicationContextInitializer could not be found

Action:

Consider the following:
        Did you build the application with enabled AOT processing?
        Is the main class com.amazonaws.services.lambda.runtime.api.client.AWSLambda correct?
        If you want to run the application in regular mode, remove the system property 'spring.aot.enabled'

Error loading class org.example.StreamLambdaHandler: java.lang.ExceptionInInitializerError
java.lang.ExceptionInInitializerError
        at java.base/java.lang.Class.forName0(Native Method)
        at java.base/java.lang.Class.forName(Unknown Source)
        at java.base/java.lang.Class.forName(Unknown Source)
Caused by: org.springframework.boot.AotInitializerNotFoundException: Startup with AOT mode enabled failed: AOT initializer com.amazonaws.services.lambda.runtime.api.client.AWSLambda__ApplicationContextInitializer could not be found
        at org.springframework.boot.SpringApplication.addAotGeneratedInitializerIfNecessary(SpringApplication.java:426)
        at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:382)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:317)
        at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:149)
        at com.amazonaws.serverless.proxy.spring.SpringBootLambdaContainerHandler.initialize(SpringBootLambdaContainerHandler.java:198)
        at com.amazonaws.serverless.proxy.InitializationWrapper.start(InitializationWrapper.java:35)
        at com.amazonaws.serverless.proxy.spring.SpringBootProxyHandlerBuilder.buildAndInitialize(SpringBootProxyHandlerBuilder.java:80)
        at com.amazonaws.serverless.proxy.spring.SpringBootLambdaContainerHandler.getAwsProxyHandler(SpringBootLambdaContainerHandler.java:96)
        at org.example.StreamLambdaHandler.<clinit>(StreamLambdaHandler.java:23)
        ... 3 more

Spring Code:

The deduceMainApplicationClass method use the StackWalker to find, in the stacktrace, the first method that has a static main.
It finds the AWS Runtime Interface Client class: com.amazonaws.services.lambda.runtime.api.client.AWSLambda so AOT looks for the wrong *__ApplicationContextInitializer

[andreaabram-eutelsat]

I deep dived a bit and I think that the issue is the missing set of the main class in this builder

serverless-java-container/aws-serverless-java-container-springboot3/src/main/java/com/amazonaws/serverless/proxy/spring/SpringBootLambdaContainerHandler.java

Lines 189 to 209 in 4696691

	public void initialize()
	throws ContainerInitializationException {
	Timer.start("SPRINGBOOT2_COLD_START");
	SpringApplicationBuilder builder = new SpringApplicationBuilder(getEmbeddedContainerClasses())
	.web(springWebApplicationType); // .REACTIVE, .SERVLET
	if (springProfiles != null) {
	builder.profiles(springProfiles);
	}
	applicationContext = builder.run();
	if (springWebApplicationType == WebApplicationType.SERVLET) {
	((AnnotationConfigServletWebServerApplicationContext)applicationContext).setServletContext(getServletContext());
	AwsServletRegistration reg = (AwsServletRegistration)getServletContext().getServletRegistration(DISPATCHER_SERVLET_REGISTRATION_NAME);
	if (reg != null) {
	reg.setLoadOnStartup(1);
	}
	}
	super.initialize();
	initialized = true;
	Timer.stop("SPRINGBOOT2_COLD_START");
	}

I tried to set that in a debug session but I get another exception

14:07:24.472 [main] INFO com.amazonaws.serverless.proxy.internal.LambdaContainerHandler -- Starting Lambda Container Handler

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/

 :: Spring Boot ::                (v3.5.7)

2025-11-11T14:08:15.760Z  INFO 16 --- [           main] c.a.s.p.s.AwsSpringWebRuntimeInitializer : AWS Handler: org.example.StreamLambdaHandler
2025-11-11T14:08:15.772Z  INFO 16 --- [           main] org.example.IssueApplication             : Starting AOT-processed IssueApplication using Java 21.0.8 with PID 16 (/var/task started by root in /var/task)
2025-11-11T14:08:15.774Z  INFO 16 --- [           main] org.example.IssueApplication             : The following 1 profile is active: "test"
2025-11-11T14:08:16.271Z  INFO 16 --- [           main] o.s.c.f.s.w.ServerlessAutoConfiguration  : Configuring Serverless Web Container
2025-11-11T14:08:16.340Z  INFO 16 --- [           main] o.s.c.f.s.w.ServerlessAutoConfiguration  : Initializing DispatcherServlet
2025-11-11T14:08:16.341Z  INFO 16 --- [           main] o.s.c.f.s.web.ServerlessServletContext   : Initializing Spring DispatcherServlet 'dispatcherServlet'
2025-11-11T14:08:16.342Z  INFO 16 --- [           main] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2025-11-11T14:08:17.311Z  INFO 16 --- [           main] o.s.web.servlet.DispatcherServlet        : Completed initialization in 964 ms
2025-11-11T14:08:17.312Z  INFO 16 --- [           main] o.s.c.f.s.w.ServerlessAutoConfiguration  : Initalized DispatcherServlet
2025-11-11T14:08:17.632Z  INFO 16 --- [           main] org.example.IssueApplication             : Started IssueApplication in 5.181 seconds (process running for 61.513)
Error loading class org.example.StreamLambdaHandler: java.lang.ExceptionInInitializerError
java.lang.ExceptionInInitializerError
        at java.base/java.lang.Class.forName0(Native Method)
        at java.base/java.lang.Class.forName(Unknown Source)
        at java.base/java.lang.Class.forName(Unknown Source)
Caused by: java.lang.ClassCastException: class org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext cannot be cast to class org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext (org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext and org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext are in unnamed module of loader com.amazonaws.services.lambda.runtime.api.client.CustomerClassLoader @3108bc)
        at com.amazonaws.serverless.proxy.spring.SpringBootLambdaContainerHandler.initialize(SpringBootLambdaContainerHandler.java:200)
        at com.amazonaws.serverless.proxy.InitializationWrapper.start(InitializationWrapper.java:35)
        at com.amazonaws.serverless.proxy.spring.SpringBootProxyHandlerBuilder.buildAndInitialize(SpringBootProxyHandlerBuilder.java:80)
        at com.amazonaws.serverless.proxy.spring.SpringBootLambdaContainerHandler.getAwsProxyHandler(SpringBootLambdaContainerHandler.java:96)
        at org.example.StreamLambdaHandler.<clinit>(StreamLambdaHandler.java:23)
        ... 3 more

I think that the issue is the cast present at this line:

serverless-java-container/aws-serverless-java-container-springboot3/src/main/java/com/amazonaws/serverless/proxy/spring/SpringBootLambdaContainerHandler.java

Line 200 in 4696691

((AnnotationConfigServletWebServerApplicationContext)applicationContext).setServletContext(getServletContext());

Maybe we can edit that cast from AnnotationConfigServletWebServerApplicationContext (that cannot exists in AOT runs) to ConfigurableWebApplicationContext (that can exists also in AOT)

[andreaabram-eutelsat]

I tried to implement the fixes of the previous comment #1580 (comment)
It runs:

Picked up JAVA_TOOL_OPTIONS: -Dspring.aot.enabled=true
14:15:33.626 [main] INFO com.amazonaws.serverless.proxy.internal.LambdaContainerHandler -- Starting Lambda Container Handler

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/

 :: Spring Boot ::                (v3.5.7)

2025-11-11T14:15:34.057Z  INFO 15 --- [           main] c.a.s.p.s.AwsSpringWebRuntimeInitializer : AWS Handler: org.example.StreamLambdaHandler
2025-11-11T14:15:34.059Z  INFO 15 --- [           main] org.example.IssueApplication             : Starting AOT-processed IssueApplication using Java 21.0.8 with PID 15 (/var/task started by root in /var/task)
2025-11-11T14:15:34.060Z  INFO 15 --- [           main] org.example.IssueApplication             : The following 1 profile is active: "test"
2025-11-11T14:15:34.137Z  INFO 15 --- [           main] o.s.c.f.s.w.ServerlessAutoConfiguration  : Configuring Serverless Web Container
2025-11-11T14:15:34.146Z  INFO 15 --- [           main] o.s.c.f.s.w.ServerlessAutoConfiguration  : Initializing DispatcherServlet
2025-11-11T14:15:34.147Z  INFO 15 --- [           main] o.s.c.f.s.web.ServerlessServletContext   : Initializing Spring DispatcherServlet 'dispatcherServlet'
2025-11-11T14:15:34.147Z  INFO 15 --- [           main] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2025-11-11T14:15:34.289Z  INFO 15 --- [           main] o.s.web.servlet.DispatcherServlet        : Completed initialization in 140 ms
2025-11-11T14:15:34.289Z  INFO 15 --- [           main] o.s.c.f.s.w.ServerlessAutoConfiguration  : Initalized DispatcherServlet
2025-11-11T14:15:34.329Z  INFO 15 --- [           main] org.example.IssueApplication             : Started IssueApplication in 0.548 seconds (process running for 0.939)
2025-11-11T14:15:34.339Z  INFO 15 --- [           main] org.example.StreamLambdaHandler          : entered generic stream lambda handler
2025-11-11T14:15:34.355Z  INFO 15 --- [           main] c.a.s.p.internal.LambdaContainerHandler  : 127.0.0.1 null- null [11/11/2025:14:15:34Z] "GET / null" 200 - "-" "Custom User Agent String" combined
END RequestId: 3c17f7c6-4a24-49da-9b6b-e2b564ac4adc
REPORT RequestId: 3c17f7c6-4a24-49da-9b6b-e2b564ac4adc  Init Duration: 0.02 ms  Duration: 983.21 ms     Billed Duration: 984 ms Memory Size: 4096 MB    Max Memory Used: 4096 MB
{"statusCode": 200, "multiValueHeaders": {}, "body": "", "isBase64Encoded": false}

But it doesn't call any controller defined in the application:

Controller

@RestController
@RequestMapping("/")
public static class HelloController {
    @GetMapping
    public String hello() {
        return "Hello World";
    }
}

[andreaabram-eutelsat]

It seems that it's registering all controllers into the org.springframework.cloud.function.serverless.web.ServerlessServletWebServerFactory but the handler search into com.amazonaws.serverless.proxy.spring.embedded.ServerlessServletEmbeddedServerFactory

So they exists multiple bean of the same interface type.

Maybe the problem is this?
https://docs.spring.io/spring-framework/reference/core/aot.html

[andreaabram-eutelsat]

I tried to force define/override those beans to always using the com.amazonaws.serverless.proxy.spring.embedded.ServerlessServletEmbeddedServerFactory:

Bean

@Bean
public ServletWebServerFactory test() {
    return new ServerlessServletEmbeddedServerFactory();
}

Log

14:23:50.159 [main] INFO com.amazonaws.serverless.proxy.internal.LambdaContainerHandler -- Starting Lambda Container Handler

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/

 :: Spring Boot ::                (v3.5.7)

2025-11-11T14:23:50.573Z  INFO 15 --- [           main] c.a.s.p.s.AwsSpringWebRuntimeInitializer : AWS Handler: org.example.StreamLambdaHandler
2025-11-11T14:23:50.575Z  INFO 15 --- [           main] org.example.IssueApplication             : Starting AOT-processed IssueApplication using Java 21.0.8 with PID 15 (/var/task started by root in /var/task)
2025-11-11T14:23:50.576Z  INFO 15 --- [           main] org.example.IssueApplication             : The following 1 profile is active: "test"
2025-11-11T14:23:50.670Z  INFO 15 --- [           main] c.a.s.p.i.servlet.AwsServletContext      : Initializing Spring embedded WebApplicationContext
2025-11-11T14:23:50.671Z  INFO 15 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 93 ms
2025-11-11T14:23:50.851Z  INFO 15 --- [           main] org.example.IssueApplication             : Started IssueApplication in 0.565 seconds (process running for 0.892)
2025-11-11T14:23:50.854Z  INFO 15 --- [           main] c.a.s.p.i.servlet.AwsServletContext      : Initializing Spring DispatcherServlet 'dispatcherServlet'
2025-11-11T14:23:50.854Z  INFO 15 --- [           main] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2025-11-11T14:23:50.855Z  INFO 15 --- [           main] o.s.web.servlet.DispatcherServlet        : Completed initialization in 0 ms
2025-11-11T14:23:50.862Z  INFO 15 --- [           main] org.example.StreamLambdaHandler          : entered generic stream lambda handler
2025-11-11T14:23:50.910Z  INFO 15 --- [           main] c.a.s.p.internal.LambdaContainerHandler  : 127.0.0.1 null- null [11/11/2025:14:23:50Z] "GET / null" 200 11 "-" "Custom User Agent String" combined
END RequestId: f377af51-68fe-4365-a3d3-14e864023e72
REPORT RequestId: f377af51-68fe-4365-a3d3-14e864023e72  Init Duration: 0.02 ms  Duration: 966.03 ms     Billed Duration: 967 ms Memory Size: 4096 MB    Max Memory Used: 4096 MB
{"statusCode": 200, "multiValueHeaders": {"Content-Length": ["11"], "Content-Type": ["text/plain; charset=UTF-8"]}, "body": "Hello World", "isBase64Encoded": false}

In this case it calls the expected controller!

[andreaabram-eutelsat]

I deep dived a bit and I think that the issue is the missing set of the main class in this builder

Maybe we can edit that cast from AnnotationConfigServletWebServerApplicationContext (that cannot exists in AOT runs) to ConfigurableWebApplicationContext (that can exists also in AOT)

I don't know if those fixes are good
If so I can do a PR

[andreaabram-eutelsat]

I don't have any idea how to solve the servlet factory bean issue 🤔

[andreaabram-eutelsat]

I don't have any idea how to solve the servlet factory bean issue 🤔

This can be "fixed" in a better way, than redefining the bean, with an @Import on the spring application:

@SpringBootApplication
@Import({ServerlessServletEmbeddedServerFactory.class})
public class IssueApplication {
    public static void main(String[] args) {
        SpringApplication.run(IssueApplication.class, args);
    }
}

Maybe It can be useful to explicit this import in documentation?