Document explicit @ModelAttribute is required for reflection hints inference

[xuyixun]

code https://github.com/xuyixun/demo-graalvm-java
spring boot: 3.2.0
gradle: 8.5

public class TestDto{
  private String name;
  //get and set
}
@RequestMapping("/demo")
public String demo(TestDto dto){
   System.out.println(dto.getName());
   return "success";
 }

Hi Spring Team,I run Demo with gradle bootRun is fine. Then build Demo with gradle bootBuildImage is fine. But when run docker image and request 127.0.0.1:8080/demo or http://127.0.0.1:8080/demo?name=test with error causes

java.lang.IllegalStateException: No primary or single unique constructor found for class com.example.demo.dto.TestDto
        at org.springframework.beans.BeanUtils.getResolvableConstructor(BeanUtils.java:267) ~[na:na]
        at org.springframework.validation.DataBinder.createObject(DataBinder.java:924) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.validation.DataBinder.construct(DataBinder.java:903) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.bind.ServletRequestDataBinder.construct(ServletRequestDataBinder.java:112) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.servlet.mvc.method.annotation.ServletModelAttributeMethodProcessor.constructAttribute(ServletModelAttributeMethodProcessor.java:156) ~[na:na]
        at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.resolveArgument(ModelAttributeMethodProcessor.java:148) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:122) ~[na:na]
        at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:218) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:171) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:917) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:829) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1089) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:979) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903) ~[com.example.demo.DemoApplication:6.1.1]
        at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564) ~[com.example.demo.DemoApplication:6.0]
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885) ~[com.example.demo.DemoApplication:6.1.1]
        at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) ~[com.example.demo.DemoApplication:6.0]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:205) ~[na:na]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149) ~[na:na]
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) ~[com.example.demo.DemoApplication:10.1.16]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174) ~[na:na]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149) ~[na:na]
        at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[com.example.demo.DemoApplication:6.1.1]
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[com.example.demo.DemoApplication:6.1.1]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174) ~[na:na]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149) ~[na:na]
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167) ~[na:na]
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90) ~[na:na]
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482) ~[com.example.demo.DemoApplication:10.1.16]
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115) ~[na:na]
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93) ~[com.example.demo.DemoApplication:10.1.16]
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[na:na]
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:340) ~[na:na]
        at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:391) ~[na:na]
        at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) ~[com.example.demo.DemoApplication:10.1.16]
        at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:896) ~[na:na]
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1744) ~[na:na]
        at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) ~[com.example.demo.DemoApplication:10.1.16]
        at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[na:na]
        at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[na:na]
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[na:na]
        at [email protected]/java.lang.Thread.runWith(Thread.java:1596) ~[com.example.demo.DemoApplication:na]
        at [email protected]/java.lang.Thread.run(Thread.java:1583) ~[com.example.demo.DemoApplication:na]
        at org.graalvm.nativeimage.builder/com.oracle.svm.core.thread.PlatformThreads.threadStartRoutine(PlatformThreads.java:837) ~[com.example.demo.DemoApplication:na]
        at org.graalvm.nativeimage.builder/com.oracle.svm.core.posix.thread.PosixPlatformThreads.pthreadStartRoutine(PosixPlatformThreads.java:211) ~[na:na]

[quaff]

You can reproduce it by gradle nativeRun, nothing to do with docker.

[mhalbritter]

There's a @RequestBody annotation missing on your controller method:

@RequestMapping("/demo")
public String demo(@RequestBody TestDto dto){
// ...

[quaff]

There's a @RequestBody annotation missing on your controller method:

@RequestMapping("/demo")
public String demo(@RequestBody TestDto dto){
// ...

It's intentional, then parameters from request will be used instead of request body.

[xuyixun]

@mhalbritter I want use get request and url parameters like http://127.0.0.1:8080/demo?name=test not post request. This
code run in jvm is fine, But in graalvm is fail

[quaff]

If you change return type from String to TestDto like this:

  public TestDto demo(TestDto dto){
    return dto;
  }

It works both with bootRun and nativeRun.

[mhalbritter]

Sorry, my bad. Then this looks like a bug to me.

[wilkinsona]

I suspect it's a bug/limitation of Framework's ControllerMappingReflectiveProcessor.

[mhalbritter]

I agree, this belongs to Spring Framework.

Workaround: Annotate your main class with @RegisterReflectionForBinding(TestDto.class).

[sdeleuze]

This is a known and almost "by design" limitation of ControllerMappingReflectiveProcessor (see #28623 related implementation) since the programming model induced by the catch-all instantiation of ServletModelAttributeMethodProcessor and ModelAttributeMethodArgumentResolver with useDefaultResolution set to true is not something, as far as I can tell, that we can support in a maintainable way. And our past tries to add reflection binding hints to all web handler method parameters has always been a failure due to a very significant increase of the footprint due to much methods reachable.

As a consequence, I suggest that we recommend and document for GraalVM use case explicit annotation with @ModelAttribute in order to allow automatic reflection hint generation.

As discussed with @mhalbritter, I suggest we add in the web section of Spring Boot GraalVM wiki:

Optional usage of @ModelAttribute as supported by Spring MVC and Spring WebFlux does not allow ahead-of-time inference of related data binding reflection hints. As a consequence, it is recommended to annotate explicitly with @ModelAttribute method parameters where binding is required when compiling to GraalVM native images.

I will also update those Spring Framework reference pages to document that limitation.

[mhalbritter]

I've updated the wiki page on Spring Boot side.