Nullpointer Exceptions on Spring Cloud Function when calling sam local

Question

i am trying to get a Spring Function runnin von AWS sam local, however even though i got a handler and an exposed function Bean i am constantly getting a Nullpointer.

@SpringBootApplication
public class DemoApplication {

  public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
  }

}

Handler Class

public class CoolSentenceHandler extends SpringBootRequestHandler<Map<String, String>, String> {


}

Function

@Component("coolSentenceFunction")
public class CoolSentenceFunction implements Function<Map<String, String>, String> {

  @Override
  public String apply(Map<String, String> unused) {
    return "HELLO WORLD";
  }
}

Template

Resources:
  Function:
    Type: AWS::Serverless::Function
    Properties:
      Timeout: 503
      MemorySize: 3008
      FunctionName: coolSentenceFunction
      Handler: com.example.demo.ui.CoolSentenceHandler
      CodeUri: /Users/blabla/Desktop/JavaProjects/POC/demo
      Runtime: java11
      Architectures:
        - x86_64

SAM call

sam local invoke coolSentenceFunction

The Exception

{"errorMessage":"java.lang.NullPointerException","errorType":"java.lang.NullPointerException","stackTrace":["org.springframework.cloud.function.adapter.aws.SpringBootRequestHandler.acceptsInput(SpringBootRequestHandler.java:77)","org.springframework.cloud.function.adapter.aws.SpringBootRequestHandler.handleRequest(SpringBootRequestHandler.java:55)"]}