Question

I have a REST service project integrated with spring. I am trying to integrate bean validation. I have made a custom annotation:

 /**
  * Denotes a field as being no empty.
  *
  * @author pguzun
  */
 @Target({METHOD, FIELD, ANNOTATION_TYPE})
 @Retention(RUNTIME)
 @Constraint(validatedBy = {INotEmptyValidator.class})
 public @interface NotEmpty {

    Error error() default Error.ServerError;

    String message() default "{error.notEmpty}";

    Class<?>[] groups() default {};

    Class<? extends Payload>[] payload() default {};
}

With

@Constraint(validatedBy = {INotEmptyValidator.class})

I specified the validator interface.

This is the validator implementation.

 /**
  * Checks that a String is not empty.
  *
  * @see StringUtils#isEmpty(java.lang.CharSequence)
  * @author pguzun
  */
@Component
public class NotEmptyValidatorImpl implements INotEmptyValidator {


 @Override
 public void initialize(NotEmpty notEmpty) {
     // NOTHING TO DO
 }

 @Override
 public boolean isValid(String value, ConstraintValidatorContext context) {
     return !StringUtils.isEmpty(value);
 }
}

I did make a custom Validator Constraint Factory

    /**
    * Is custom an {@link ConstraintValidatorFactory }. Engine for defining factory
    * methods for {@link ConstraintValidator}'s.
    *
    * @author pguzun
    */
    public class NeoSpringConstraintValidatorFactory implements ConstraintValidatorFactory, ApplicationContextAware {

        private ApplicationContext applicationContext;

        public NeoSpringConstraintValidatorFactory() {
        }

        @Override
        public <T extends ConstraintValidator<?, ?>> T getInstance(Class<T> key) {
            Map<String, T> beansByNames = applicationContext.getBeansOfType(key);
            if (beansByNames.isEmpty()) {
                try {
                    return key.newInstance();
                } catch (InstantiationException e) {
                    throw new RuntimeException("Could not instantiate constraint validator class '" + key.getName() + "'", e);
                } catch (IllegalAccessException e) {
                    throw new RuntimeException("Could not instantiate constraint validator class '" + key.getName() + "'", e);
                }
            }
            if (beansByNames.size() > 1) {
                throw new RuntimeException("Only one bean of type '" + key.getName() + "' is allowed in the application context");
            }
            return (T) beansByNames.values().iterator().next();
        }

        @Override
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
            Assert.notNull(applicationContext, "applicationContext can not be null");
            this.applicationContext = applicationContext;
        }
    }

and configured it like this

<bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean" >
    <property name="constraintValidatorFactory" ref="constraintValidatorFactory"/> 
</bean>
<bean id="constraintValidatorFactory" class="com...NeoSpringConstraintValidatorFactory" >
</bean>

When I invoke validate in service on a bean that has a field annotated like this

/**
* The User's value object definition
*
* @author pguzun
*/
@XmlRootElement()
@XmlAccessorType(XmlAccessType.FIELD)
public class UserVO {

    @XmlElement
    private long id;
    @NotEmpty(error = Error.EmailVoid)
    private String email;   

I get

    SEVERE: Servlet.service() for servlet jersey-serlvet threw exception
    javax.validation.ValidationException: HV000032: Unable to initialize com.backend.rest.validation.validator.NotEmptyValidatorImpl.
        at org.hibernate.validator.internal.engine.ConstraintTree.initializeConstraint(ConstraintTree.java:450)
        at org.hibernate.validator.internal.engine.ConstraintTree.createAndInitializeValidator(ConstraintTree.java:352)
        at org.hibernate.validator.internal.engine.ConstraintTree.getInitializedValidator(ConstraintTree.java:334)
        at org.hibernate.validator.internal.engine.ConstraintTree.validateConstraints(ConstraintTree.java:155)
        at org.hibernate.validator.internal.engine.ConstraintTree.validateConstraints(ConstraintTree.java:125)
        at org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:86)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:442)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:387)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:351)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:303)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:133)
        at org.springframework.validation.beanvalidation.SpringValidatorAdapter.validate(SpringValidatorAdapter.java:194)
        at com.backend.rest.UserResourceImpl.validateGuest(UserResourceImpl.java:100)
        at com.backend.rest.UserResourceImpl.register(UserResourceImpl.java:77)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
        at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
        at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
        at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)
        at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
        at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
        at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1483)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1414)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1363)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1353)
        at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:414)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:708)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
        at org.apache.catalina.core.StandardContextValve.__invoke(StandardContextValve.java:191)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
        at java.lang.Thread.run(Thread.java:662)
    Caused by: java.lang.ClassCastException: $Proxy84 cannot be cast to com.backend.rest.validation.validator.NotEmpty
        at com.backend.rest.validation.validator.NotEmptyValidatorImpl.initialize(NotEmptyValidatorImpl.java:18)
        at org.hibernate.validator.internal.engine.ConstraintTree.initializeConstraint(ConstraintTree.java:447)
        ... 49 more
    Jun 4, 2012 1:36:57 PM org.apache.catalina.core.StandardWrapperValve invoke
    SEVERE: Servlet.service() for servlet jersey-serlvet threw exception
    javax.validation.ValidationException: HV000032: Unable to initialize com.backend.rest.validation.validator.NotEmptyValidatorImpl.
        at org.hibernate.validator.internal.engine.ConstraintTree.initializeConstraint(ConstraintTree.java:450)
        at org.hibernate.validator.internal.engine.ConstraintTree.createAndInitializeValidator(ConstraintTree.java:352)
        at org.hibernate.validator.internal.engine.ConstraintTree.getInitializedValidator(ConstraintTree.java:334)
        at org.hibernate.validator.internal.engine.ConstraintTree.validateConstraints(ConstraintTree.java:155)
        at org.hibernate.validator.internal.engine.ConstraintTree.validateConstraints(ConstraintTree.java:125)
        at org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:86)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:442)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:387)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:351)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:303)
        at org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:133)
        at org.springframework.validation.beanvalidation.SpringValidatorAdapter.validate(SpringValidatorAdapter.java:194)
        at com.backend.rest.UserResourceImpl.validateGuest(UserResourceImpl.java:100)
        at com.backend.rest.UserResourceImpl.register(UserResourceImpl.java:77)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
        at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
        at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
        at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)
        at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
        at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
        at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1483)
        at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1414)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1363)
        at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1353)
        at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:414)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
        at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:708)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
        at org.apache.catalina.core.StandardContextValve.__invoke(StandardContextValve.java:191)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
        at java.lang.Thread.run(Thread.java:662)
    Caused by: java.lang.ClassCastException: $Proxy84 cannot be cast to com.backend.rest.validation.validator.NotEmpty
        at com.backend.rest.validation.validator.NotEmptyValidatorImpl.initialize(NotEmptyValidatorImpl.java:18)
        at org.hibernate.validator.internal.engine.ConstraintTree.initializeConstraint(ConstraintTree.java:447)
        ... 49 more

and I know java.lang.ClassCastException: $Proxy84 cannot be cast to Clazz is a clasic spring exception when you don’t use interfaces
but here I do use and NotEmpty si an annotation

Please tell what do I do wrong?

ps. I use this versions of frameworks

   <properties>
    <spring.version>3.1.1.RELEASE</spring.version>
    <hibernate.version>4.1.3.Final</hibernate.version>
    <jersey.version>1.12</jersey.version>
    <validation.api.version>1.0.0.GA</validation.api.version>
    <hibernate.validator.version>4.3.0.Final</hibernate.validator.version>

Answer 1

I want to thank you each for spending time on this issue.

The error comes from others implemented annotations that have this constraint validator.
@Constraint(validatedBy = {INotEmptyValidator.class}).
This was done for sure by mistake.

Finally This is the good exemple of doing bean validation specifying constratint validator @Constraint(validatedBy = {INotEmptyValidator.class}) as interface.
The implementation NotEmptyValidatorImpl is a spring bean.