Spring ResolvableType.forClass(converterClass).as(genericIfc) could not get lamda type info

@Configuration
public class LocalDateConverterConfig {

    @Bean
    public Converter<String, LocalDate> localDateConverter() {
        return source -> LocalDate.parse(source, DateTimeFormatter.ofPattern("yyyy-MM-dd"));
    }

    @Bean
    public Converter<String, LocalDateTime> localDateTimeConverter() {
        return source -> LocalDateTime.parse(source, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    }

}

when i start the application, i got an exception:

Caused by: java.lang.IllegalArgumentException: Unable to determine source type <S> and target type <T> for your Converter [com.maxiao.config.LocalDateConverterConfig$$Lambda$595/1561854103]; does the class parameterize those types?

It seems like that it does not support lamda expressions. any one help?

here is the stack trace

Caused by: java.lang.IllegalArgumentException: Unable to determine source type <S> and target type <T> for your Converter [com.maxiao.config.LocalDateConverterConfig$$Lambda$595/1561854103]; does the class parameterize those types?
    at org.springframework.core.convert.support.GenericConversionService.addConverter(GenericConversionService.java:92) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.addFormatters(WebMvcAutoConfiguration.java:302) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.web.servlet.config.annotation.WebMvcConfigurerComposite.addFormatters(WebMvcConfigurerComposite.java:81) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration.addFormatters(DelegatingWebMvcConfiguration.java:78) ~[spring-webmvc-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration.mvcConversionService(WebMvcAutoConfiguration.java:479) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration$$EnhancerBySpringCGLIB$$b85a4d01.CGLIB$mvcConversionService$0(<generated>) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration$$EnhancerBySpringCGLIB$$b85a4d01$$FastClassBySpringCGLIB$$c93fbff1.invoke(<generated>) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) ~[spring-core-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:363) ~[spring-context-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    at org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration$$EnhancerBySpringCGLIB$$b85a4d01.mvcConversionService(<generated>) ~[spring-boot-autoconfigure-2.1.7.RELEASE.jar:2.1.7.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_212]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_212]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_212]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_212]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.1.9.RELEASE.jar:5.1.9.RELEASE]
    ... 52 common frames omitted

Comment From: andluu

Hello! You should use anonymous class instead. It's not ResolvableType's issue. The ResolvableType uses JDK's Class#getGenericInterfaces(). That is, due to generic information that are transmitted from the bytecode to the runtime (the lambda metafactory) are not kept inside the lambda class (a lambda class may be shared by several different lambdas). You can read more here.

Comment From: refeccd

Hello! You should use anonymous class instead. It's not ResolvableType's issue. The ResolvableType uses JDK's Class#getGenericInterfaces(). That is, due to generic information that are transmitted from the bytecode to the runtime (the lambda metafactory) are not kept inside the lambda class (a lambda class may be shared by several different lambdas). You can read more here.

Thanks, I will look at this document.