SpringValidatorAdapter bug? Validating collection of Strings - spring-boot

Question

Say that our http request data are:
{
"a": ["a", "b", "c"]
}
corresponding DTO could be:
#Data //lombok
public class DTO {
private List<String> a;
}
but we want to validate this as well, including elements in collection, which should be possible with Java Bean Validation 2.0 and (IIRC) from hibernate-validator 6.0.1. So lets add annotations:
#Data
public class DTO {
#NotEmpty
private List<#NotBlank String> a;
}
however, this does not work neither in our "2.2.2.RELEASE" nor in newest "2.3.0.RELEASE".
This method: org.springframework.validation.beanvalidation.SpringValidatorAdapter#processConstraintViolations will correctly receive ConstraintViolation(below is its toString):
ConstraintViolationImpl{interpolatedMessage='must not be blank', propertyPath=a[0].<list element>, rootBeanClass=class DTO, messageTemplate='{javax.validation.constraints.NotBlank.message}'}
so it means that hibernate-validator is OK, however it continues with with its logic, and calculates field related to this error to be: a[0]. When we drill deeper, we can find org.springframework.beans.CachedIntrospectionResults#getPropertyDescriptor trying to find propertyDescriptor named "a" or "A" failing to find it. I thought it might be caused by used lombok, so I added setters/getters manually, but no change. Full delombok did not help either, and this is all I can do to help with PropertyDescriptors. Everything what could be searched for is in the class declared.
Is it a bug? Do I have something set incorrectly? Does SpringBoot need some help to be able to process such bean validation?
Produced exception:
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalStateException: JSR-303 validated property 'a[0]' does not have a corresponding accessor for Spring data binding - check your DataBinder's configuration (bean property versus direct field access)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at brave.servlet.TracingFilter.doFilter(TracingFilter.java:65)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:320)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:126)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:118)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:158)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilterInternal(BasicAuthenticationFilter.java:204)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:92)
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:77)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:358)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:271)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.cloud.sleuth.instrument.web.ExceptionLoggingFilter.doFilter(ExceptionLoggingFilter.java:50)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at brave.servlet.TracingFilter.doFilter(TracingFilter.java:82)
at org.springframework.cloud.sleuth.instrument.web.LazyTracingFilter.doFilter(TraceWebServletAutoConfiguration.java:138)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalStateException: JSR-303 validated property 'a[0]' does not have a corresponding accessor for Spring data binding - check your DataBinder's configuration (bean property versus direct field access)
at org.springframework.validation.beanvalidation.SpringValidatorAdapter.processConstraintViolations(SpringValidatorAdapter.java:188)
at org.springframework.validation.beanvalidation.SpringValidatorAdapter.validate(SpringValidatorAdapter.java:109)
at org.springframework.validation.ValidationUtils.invokeValidator(ValidationUtils.java:89)
at org.springframework.validation.ValidationUtils.invokeValidator(ValidationUtils.java:56)
at ...our code...
at org.springframework.validation.DataBinder.validate(DataBinder.java:892)
at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.validateIfApplicable(AbstractMessageConverterMethodArgumentResolver.java:266)
at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:137)
at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)
at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:167)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
... 87 common frames omitted
Caused by: org.springframework.beans.NotReadablePropertyException: Invalid property 'a[0]' of bean class [java.util.ArrayList]: Bean property 'a[0]' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter?
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyValue(AbstractNestablePropertyAccessor.java:622)
at org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyValue(AbstractNestablePropertyAccessor.java:612)
at org.springframework.validation.AbstractPropertyBindingResult.getActualFieldValue(AbstractPropertyBindingResult.java:104)
at org.springframework.validation.AbstractBindingResult.getRawFieldValue(AbstractBindingResult.java:284)
at org.springframework.validation.beanvalidation.SpringValidatorAdapter.getRejectedValue(SpringValidatorAdapter.java:318)
at org.springframework.validation.beanvalidation.SpringValidatorAdapter.processConstraintViolations(SpringValidatorAdapter.java:174)
... 104 common frames omitted
Expected behavior — as any other bean validation issue.
UPDATE — so definitely not a bug. I created "same" field in different DTO being processed via different, but equally annotated, controller, and it works. Placement into different modules also does not seem to produce different result. I'll retry lombok. So far I have no idea why it fails.
UPDATE — I think I found some clue:
if I have controller method defined as this:
public void accept(#RequestBody #Valid DTO dtos) {
it works just fine. However if I have it like this:
public void accept(#RequestBody #Valid List<DTO> dtos) {
if fails as described. By default this is not validated, sure. What we have here to enable this validations are these 2 classes:
#ControllerAdvice
public class ValidatorAdvice {
private final LocalValidatorFactoryBean validator;
#SuppressWarnings("SpringJavaInjectionPointsAutowiringInspection")
public ValidatorAdvice(LocalValidatorFactoryBean validator) {
this.validator = validator;
}
/**
* Adds the {#link CollectionValidator} to the supplied
* {#link WebDataBinder}
*
* #param binder web data binder.
*/
#InitBinder
public void initBinder(WebDataBinder binder) {
if (binder.getTarget() instanceof Collection) {
binder.addValidators(new CollectionValidator(validator));
}
}
}
and
import java.util.Collection;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
public class CollectionValidator implements Validator {
private final Validator validator;
public CollectionValidator(LocalValidatorFactoryBean validatorFactory) {
this.validator = validatorFactory;
}
#Override
public boolean supports(Class<?> clazz) {
return Collection.class.isAssignableFrom(clazz);
}
/**
* Validate each element inside the supplied {#link Collection}.
*
* The supplied errors instance is used to report the validation errors.
*
* #param target the collection that is to be validated
* #param errors contextual state about the validation process
*/
#Override
#SuppressWarnings("rawtypes")
public void validate(Object target, Errors errors) {
Collection collection = (Collection) target;
for (Object object : collection) {
ValidationUtils.invokeValidator(validator, object, errors);
}
}
}
these will do the validation of all DTO in dto list (#RequestBody #Valid List<DTO> dtos), but somehow it messes with the validation. Any ideas why is it like this, or how to do it correctly (if this is incorrect way)?