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Validation with Hibernate Validator

This guide covers how to use Hibernate Validator/Bean Validation for:

validating the input/output of your REST services;
validating the parameters and return values of the methods of your business services.

Prerequisites

To complete this guide, you need:

Roughly 15 minutes
An IDE
JDK 17+ installed with JAVA_HOME configured appropriately
Apache Maven 3.9.9
Optionally the Quarkus CLI if you want to use it
Optionally Mandrel or GraalVM installed and configured appropriately if you want to build a native executable (or Docker if you use a native container build)

Architecture

The application built in this guide is quite simple. The user fills a form on a web page. The web page sends the form content to the BookResource as JSON (using Ajax). The BookResource validates the user input and returns the result as JSON.

Architecture

Solution

We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.

Clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git, or download an archive.

The solution is located in the validation-quickstart directory.

Creating the Maven project

First, we need a new project. Create a new project with the following command:

CLI

quarkus create app org.acme:validation-quickstart \
    --extension='rest-jackson,hibernate-validator' \
    --no-code
cd validation-quickstart

To create a Gradle project, add the --gradle or --gradle-kotlin-dsl option.

For more information about how to install and use the Quarkus CLI, see the Quarkus CLI guide.

Maven

mvn io.quarkus.platform:quarkus-maven-plugin:3.16.4:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=validation-quickstart \
    -Dextensions='rest-jackson,hibernate-validator' \
    -DnoCode
cd validation-quickstart

To create a Gradle project, add the -DbuildTool=gradle or -DbuildTool=gradle-kotlin-dsl option.

For Windows users:

If using cmd, (don’t use backward slash \ and put everything on the same line)
If using Powershell, wrap -D parameters in double quotes e.g. "-DprojectArtifactId=validation-quickstart"

This command generates a Maven structure importing the Quarkus REST (formerly RESTEasy Reactive)/Jakarta REST, Jackson and Hibernate Validator/Bean Validation extensions.

If you already have your Quarkus project configured, you can add the hibernate-validator extension to your project by running the following command in your project base directory:

CLI

quarkus extension add hibernate-validator

Maven

./mvnw quarkus:add-extension -Dextensions='hibernate-validator'

Gradle

./gradlew addExtension --extensions='hibernate-validator'

This will add the following to your build file:

pom.xml

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-hibernate-validator</artifactId>
</dependency>

build.gradle

implementation("io.quarkus:quarkus-hibernate-validator")

Constraints

In this application, we are going to test an elementary object, but we support complicated constraints and can validate graphs of objects. Create the org.acme.validation.Book class with the following content:

package org.acme.validation;

import jakarta.validation.constraints.NotBlank;
import jakarta.validation.constraints.Min;

public class Book {

    @NotBlank(message="Title may not be blank")
    public String title;

    @NotBlank(message="Author may not be blank")
    public String author;

    @Min(message="Author has been very lazy", value=1)
    public double pages;
}

Constraints are added on fields, and when an object is validated, the values are checked. The getter and setter methods are also used for JSON mapping.

JSON mapping and validation

Create the following REST resource as org.acme.validation.BookResource:

package org.acme.validation;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

@Path("/books")
public class BookResource {

    @Inject
    Validator validator; (1)

    @Path("/manual-validation")
    @POST
    public Result tryMeManualValidation(Book book) {
        Set<ConstraintViolation<Book>> violations = validator.validate(book);
        if (violations.isEmpty()) {
            return new Result("Book is valid! It was validated by manual validation.");
        } else {
            return new Result(violations);
        }
    }
}

1	The `Validator` instance is injected via CDI.

Yes it does not compile, Result is missing, but we will add it very soon.

The method parameter (book) is created from the JSON payload automatically.

The method uses the Validator instance to check the payload. It returns a set of violations. If this set is empty, it means the object is valid. In case of failures, the messages are concatenated and sent back to the browser.

Let’s now create the Result class as an inner class:

public static class Result {

    Result(String message) {
        this.success = true;
        this.message = message;
    }

    Result(Set<? extends ConstraintViolation<?>> violations) {
        this.success = false;
        this.message = violations.stream()
             .map(cv -> cv.getMessage())
             .collect(Collectors.joining(", "));
    }

    private String message;
    private boolean success;

    public String getMessage() {
        return message;
    }

    public boolean isSuccess() {
        return success;
    }

}

The class is very simple and only contains 2 fields and the associated getters and setters. Because we indicate that we produce JSON, the mapping to JSON is made automatically.

REST end point validation

While using the Validator manually might be useful for some advanced usage, if you simply want to validate the parameters or the return value or your REST end point, you can annotate it directly, either with constraints (@NotNull, @Digits…) or with @Valid (which will cascade the validation to the bean).

Let’s create an end point validating the Book provided in the request:

@Path("/end-point-method-validation")
@POST
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public Result tryMeEndPointMethodValidation(@Valid Book book) {
    return new Result("Book is valid! It was validated by end point method validation.");
}

As you can see, we don’t have to manually validate the provided Book anymore as it is automatically validated.

If a validation error is triggered, a violation report is generated and serialized as JSON as our end point produces a JSON output. It can be extracted and manipulated to display a proper error message.

An example of such a report could be:

{
    "title": "Constraint Violation",
    "status": 400,
    "violations": [
        {
            "field": "tryMeEndPointMethodValidation.book.title",
            "message": "Title cannot be blank"
        }
    ]
}

This response is produced by Quarkus via a builtin implementation of jakarta.ws.rs.ext.ExceptionMapper. If the application code needs to handle ValidationException in some custom way, it can provide an implementation of jakarta.ws.rs.ext.ExceptionMapper like so:

import jakarta.validation.ValidationException;
import jakarta.ws.rs.core.Response;
import jakarta.ws.rs.ext.ExceptionMapper;
import jakarta.ws.rs.ext.Provider;

@Provider
public class ResteasyReactiveViolationExceptionMapper implements ExceptionMapper<ValidationException> {

    @Override
    public Response toResponse(ValidationException exception) {
        // TODO: implement
    }
}

Service method validation

It might not always be handy to have the validation rules declared at the end point level as it could duplicate some business validation.

The best option is then to annotate a method of your business service with your constraints (or in our particular case with @Valid):

package org.acme.validation;

import jakarta.enterprise.context.ApplicationScoped;
import jakarta.validation.Valid;

@ApplicationScoped
public class BookService {

    public void validateBook(@Valid Book book) {
        // your business logic here
    }
}

Calling the service in your rest end point triggers the Book validation automatically:

@Inject BookService bookService;

@Path("/service-method-validation")
@POST
public Result tryMeServiceMethodValidation(Book book) {
    try {
        bookService.validateBook(book);
        return new Result("Book is valid! It was validated by service method validation.");
    } catch (ConstraintViolationException e) {
        return new Result(e.getConstraintViolations());
    }
}

Note that, if you want to push the validation errors to the frontend, you have to catch the exception and push the information yourselves as they will not be automatically pushed to the JSON output.

Keep in mind that you usually don’t want to expose to the public the internals of your services - and especially not the validated value contained in the violation object.

A frontend

Now let’s add the simple web page to interact with our BookResource. Quarkus automatically serves static resources contained in the META-INF/resources directory. In the src/main/resources/META-INF/resources directory, replace the index.html file with the content from this index.html file in it.

Run the application

Now, let’s see our application in action. Run it with:

CLI

quarkus dev

Maven

./mvnw quarkus:dev

Gradle

./gradlew --console=plain quarkusDev

Then, open your browser to http://localhost:8080/:

Enter the book details (valid or invalid)
Click on the Try me… buttons to check if your data is valid using one of the methods we presented above.

Application

The application can be packaged using:

CLI

quarkus build

Maven

./mvnw install

Gradle

./gradlew build

and executed using java -jar target/quarkus-app/quarkus-run.jar.

You can also build the native executable using:

CLI

quarkus build --native

Maven

./mvnw install -Dnative

Gradle

./gradlew build -Dquarkus.native.enabled=true

Going further

Hibernate Validator extension and CDI

The Hibernate Validator extension is tightly integrated with CDI.

Configuring the ValidatorFactory

Sometimes, you might need to configure the behavior of the ValidatorFactory, for instance to use a specific ParameterNameProvider.

While the ValidatorFactory is instantiated by Quarkus itself, you can very easily tweak it by declaring replacement beans that will be injected in the configuration.

If you create a bean of the following types in your application, it will automatically be injected into the ValidatorFactory configuration:

jakarta.validation.ClockProvider
jakarta.validation.ConstraintValidator
jakarta.validation.ConstraintValidatorFactory
jakarta.validation.MessageInterpolator
jakarta.validation.ParameterNameProvider
jakarta.validation.TraversableResolver
org.hibernate.validator.spi.properties.GetterPropertySelectionStrategy
org.hibernate.validator.spi.nodenameprovider.PropertyNodeNameProvider
org.hibernate.validator.spi.scripting.ScriptEvaluatorFactory

You don’t have to wire anything.

Obviously, for each listed type, you can declare only one bean.

Most of the time, these beans should be declared as @ApplicationScoped.

However, in the case of ConstraintValidators that are dependent of attributes of the constraint annotation (typically when implementing the initialize(A constraintAnnotation) method), use the @Dependent scope to make sure each annotation context has a separate instance of the ConstraintValidator bean.

If customizing the ValidatorFactory through the available configuration properties and the CDI beans above doesn’t cover your requirements, you can customize it further by registering ValidatorFactoryCustomizer beans.

For instance, you could override the built-in validator enforcing the @Email constraint and use MyEmailValidator instead with the following class:

@ApplicationScoped
public class MyEmailValidatorFactoryCustomizer implements ValidatorFactoryCustomizer {

    @Override
    public void customize(BaseHibernateValidatorConfiguration<?> configuration) {
        ConstraintMapping constraintMapping = configuration.createConstraintMapping();

        constraintMapping
                .constraintDefinition(Email.class)
                .includeExistingValidators(false)
                .validatedBy(MyEmailValidator.class);

        configuration.addMapping(constraintMapping);
    }
}

All beans implementing ValidatorFactoryCustomizer are applied, meaning you can have several of them. If you need to enforce some ordering, you can use the usual @jakarta.annotation.Priority annotation - beans with higher priority are applied first.

Constraint validators as beans

You can declare your constraint validators as CDI beans:

@ApplicationScoped
public class MyConstraintValidator implements ConstraintValidator<MyConstraint, String> {

    @Inject
    MyService service;

    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        if (value == null) {
            return true;
        }

        return service.validate(value);
    }
}

When initializing a constraint validator of a given type, Quarkus will check if a bean of this type is available and, if so, it will use it instead of instantiating a ConstraintValidator.

Thus, as demonstrated in our example, you can fully use injection in your constraint validator beans.

The scope you choose for your ConstraintValidator bean is important:

If the same instance of the ConstraintValidator bean can be used across the whole application, use the @ApplicationScoped scope.
If the ConstraintValidator bean implements the initialize(A constraintAnnotation) method and depends on the state of the constraint annotation, use the @Dependent scope to make sure each annotation context has a separate and properly configured instance of the ConstraintValidator bean.

Validation and localization

By default, constraint violation messages will be returned in the build system locale.

You can configure this behavior by adding the following configuration in your application.properties:

# The default locale to use
quarkus.default-locale=fr-FR

If you are using Quarkus REST or RESTEasy Classic, in the context of a Jakarta REST endpoint, Hibernate Validator will automatically resolve the optimal locale to use from the Accept-Language HTTP header, provided the supported locales have been properly specified in the application.properties:

# The list of all the supported locales
quarkus.locales=en-US,es-ES,fr-FR

Alternatively, you can use all to make native-image executable to include all available locales. It inflate the size of the executable substantially though. The difference between including just two or three locales and including all locales is at least 23 MB.

A similar mechanism exists for GraphQL services based on the quarkus-smallrye-graphql extension.

If this default mechanism is not sufficient and you need a custom locale resolution, you can add additional org.hibernate.validator.spi.messageinterpolation.LocaleResolvers:

Any CDI bean implementing org.hibernate.validator.spi.messageinterpolation.LocaleResolver will be taken into account.
The LocaleResolvers are consulted in the order of @Priority (higher priority goes first).
A LocaleResolver may return null if it cannot resolve the locale, it will then be ignored.
The first non-null locale returned by a LocaleResolver is the one resolved.

Validation groups for REST endpoint or service method validation

It is sometimes necessary to enable different validation constraints for the same class when it’s passed to a different method.

For example, a Book may need to have a null identifier when passed to the post method (because the identifier will be generated), but a non-null identifier when passed to the put method (because the method needs the identifier to know what to update).

To address this, you can take advantage of validation groups. Validation groups are markers that you put on your constraints in order to enable or disable them at will.

First, define the Post and Put groups, which are just Java interfaces.

public interface ValidationGroups {
    interface Post extends Default { (1)
    }
    interface Put extends Default { (1)
    }
}

1 Make the custom groups extend the Default group. This means that whenever these groups are enabled, the Default group is also enabled. This is useful if you have constraints that you want validated in both the Post and Put method: you can simply use the default group on those constraints, like on the title property below.

Then add the relevant constraints to Book, assigning the right group to each constraint:

public class Book {

    @Null(groups = ValidationGroups.Post.class)
    @NotNull(groups = ValidationGroups.Put.class)
    public Long id;

    @NotBlank
    public String title;

}

Finally, add a @ConvertGroup annotation next to your @Valid annotation in your validated method.

@Path("/")
@POST
@Consumes(MediaType.APPLICATION_JSON)
public void post(@Valid @ConvertGroup(to = ValidationGroups.Post.class) Book book) { (1)
    // ...
}

@Path("/")
@PUT
@Consumes(MediaType.APPLICATION_JSON)
public void put(@Valid @ConvertGroup(to = ValidationGroups.Put.class) Book book) { (2)
    // ...
}

1	Enable the `Post` group, meaning only constraints assigned to the `Post` (and `Default`) groups will be validated for the `book` parameter of the `post` method. In this case, it means `Book.id` must be `null` and `Book.title` must not be blank.
2	Enable the `Put` group, meaning only constraints assigned to the `Put` (and `Default`) groups will be validated for the `book` parameter of the `put` method. In this case, it means `Book.id` must not be `null` and `Book.title` must not be blank.

Limitations

META-INF/validation.xml

Configuring the ValidatorFactory using a META-INF/validation.xml file is NOT supported in Quarkus.

At the moment, Hibernate Validator does not expose an API to extract the information from this file so that we could register the appropriate classes for reflection.

To configure the ValidatorFactory, use the exposed configuration properties and the CDI integration.

Consequently, the only way to define constraints in Quarkus is by annotating your classes.

ValidatorFactory and native executables

Quarkus provides a default ValidatorFactory that you can customize using configuration properties. This ValidatorFactory is carefully initialized to support native executables using a bootstrap that is Quarkus-specific.

Creating a ValidatorFactory by yourself it not supported in native executables and if you try to do so, you will get an error similar to jakarta.validation.NoProviderFoundException: Unable to create a Configuration, because no Jakarta Bean Validation provider could be found. Add a provider like Hibernate Validator (RI) to your classpath. when running your native executable.

Thus why you should always use the Quarkus-managed ValidatorFactory by injecting an instance of ValidatorFactory or directly an instance of Validator using CDI injection.

To support some external libraries that are creating a ValidatorFactory using the default bootstrap, Quarkus returns the ValidatorFactory managed by Quarkus when Validation.buildDefaultValidatorFactory() is called.

Hibernate Validator Configuration Reference

Configuration property fixed at build time - All other configuration properties are overridable at runtime

Configuration property	Type	Default
`quarkus.hibernate-validator.fail-fast` Enable the fail fast mode. When fail fast is enabled the validation will stop on the first constraint violation detected. Environment variable: `QUARKUS_HIBERNATE_VALIDATOR_FAIL_FAST` Show more	boolean	`false`
Method validation	Type	Default
`quarkus.hibernate-validator.method-validation.allow-overriding-parameter-constraints` Define whether overriding methods that override constraints should throw a `ConstraintDefinitionException`. The default value is `false`, i.e. do not allow. See Section 4.5.5 of the JSR 380 specification, specifically In sub types (be it sub classes/interfaces or interface implementations), no parameter constraints may be declared on overridden or implemented methods, nor may parameters be marked for cascaded validation. This would pose a strengthening of preconditions to be fulfilled by the caller. Environment variable: `QUARKUS_HIBERNATE_VALIDATOR_METHOD_VALIDATION_ALLOW_OVERRIDING_PARAMETER_CONSTRAINTS` Show more	boolean	`false`
`quarkus.hibernate-validator.method-validation.allow-parameter-constraints-on-parallel-methods` Define whether parallel methods that define constraints should throw a `ConstraintDefinitionException`. The default value is `false`, i.e. do not allow. See Section 4.5.5 of the JSR 380 specification, specifically If a sub type overrides/implements a method originally defined in several parallel types of the hierarchy (e.g. two interfaces not extending each other, or a class and an interface not implemented by said class), no parameter constraints may be declared for that method at all nor parameters be marked for cascaded validation. This again is to avoid an unexpected strengthening of preconditions to be fulfilled by the caller. Environment variable: `QUARKUS_HIBERNATE_VALIDATOR_METHOD_VALIDATION_ALLOW_PARAMETER_CONSTRAINTS_ON_PARALLEL_METHODS` Show more	boolean	`false`
`quarkus.hibernate-validator.method-validation.allow-multiple-cascaded-validation-on-return-values` Define whether more than one constraint on a return value may be marked for cascading validation are allowed. The default value is `false`, i.e. do not allow. See Section 4.5.5 of the JSR 380 specification, specifically One must not mark a method return value for cascaded validation more than once in a line of a class hierarchy. In other words, overriding methods on sub types (be it sub classes/interfaces or interface implementations) cannot mark the return value for cascaded validation if the return value has already been marked on the overridden method of the super type or interface. Environment variable: `QUARKUS_HIBERNATE_VALIDATOR_METHOD_VALIDATION_ALLOW_MULTIPLE_CASCADED_VALIDATION_ON_RETURN_VALUES` Show more	boolean	`false`
Expression Language	Type	Default
`quarkus.hibernate-validator.expression-language.constraint-expression-feature-level` Configure the Expression Language feature level for constraints, allowing the selection of Expression Language features available for message interpolation. This property only affects the EL feature level of "static" constraint violation messages set through the `message` attribute of constraint annotations. In particular, it doesn’t affect the default EL feature level for custom violations created programmatically in validator implementations. The feature level for those can only be configured directly in the validator implementation. Environment variable: `QUARKUS_HIBERNATE_VALIDATOR_EXPRESSION_LANGUAGE_CONSTRAINT_EXPRESSION_FEATURE_LEVEL` Show more	`default`, `none`, `variables`, `bean-properties`, `bean-methods`	`bean-properties`

Configuration property

Type

Default

quarkus.hibernate-validator.fail-fast

Enable the fail fast mode. When fail fast is enabled the validation will stop on the first constraint violation detected.

Environment variable: QUARKUS_HIBERNATE_VALIDATOR_FAIL_FAST

boolean

false

Method validation

Type

Default

quarkus.hibernate-validator.method-validation.allow-overriding-parameter-constraints

Define whether overriding methods that override constraints should throw a ConstraintDefinitionException. The default value is false, i.e. do not allow.

See Section 4.5.5 of the JSR 380 specification, specifically

In sub types (be it sub classes/interfaces or interface implementations), no parameter constraints may be declared on overridden or implemented methods, nor may parameters be marked for cascaded validation. This would pose a strengthening of preconditions to be fulfilled by the caller.

Environment variable: QUARKUS_HIBERNATE_VALIDATOR_METHOD_VALIDATION_ALLOW_OVERRIDING_PARAMETER_CONSTRAINTS

boolean

false

quarkus.hibernate-validator.method-validation.allow-parameter-constraints-on-parallel-methods

Define whether parallel methods that define constraints should throw a ConstraintDefinitionException. The default value is false, i.e. do not allow.

See Section 4.5.5 of the JSR 380 specification, specifically

If a sub type overrides/implements a method originally defined in several parallel types of the hierarchy (e.g. two interfaces not extending each other, or a class and an interface not implemented by said class), no parameter constraints may be declared for that method at all nor parameters be marked for cascaded validation. This again is to avoid an unexpected strengthening of preconditions to be fulfilled by the caller.

Environment variable: QUARKUS_HIBERNATE_VALIDATOR_METHOD_VALIDATION_ALLOW_PARAMETER_CONSTRAINTS_ON_PARALLEL_METHODS

boolean

false

quarkus.hibernate-validator.method-validation.allow-multiple-cascaded-validation-on-return-values

Define whether more than one constraint on a return value may be marked for cascading validation are allowed. The default value is false, i.e. do not allow.

See Section 4.5.5 of the JSR 380 specification, specifically

One must not mark a method return value for cascaded validation more than once in a line of a class hierarchy. In other words, overriding methods on sub types (be it sub classes/interfaces or interface implementations) cannot mark the return value for cascaded validation if the return value has already been marked on the overridden method of the super type or interface.

Environment variable: QUARKUS_HIBERNATE_VALIDATOR_METHOD_VALIDATION_ALLOW_MULTIPLE_CASCADED_VALIDATION_ON_RETURN_VALUES

boolean

false

Expression Language

Type

Default

quarkus.hibernate-validator.expression-language.constraint-expression-feature-level

Configure the Expression Language feature level for constraints, allowing the selection of Expression Language features available for message interpolation.

This property only affects the EL feature level of "static" constraint violation messages set through the message attribute of constraint annotations.

In particular, it doesn’t affect the default EL feature level for custom violations created programmatically in validator implementations. The feature level for those can only be configured directly in the validator implementation.

Environment variable: QUARKUS_HIBERNATE_VALIDATOR_EXPRESSION_LANGUAGE_CONSTRAINT_EXPRESSION_FEATURE_LEVEL

default, none, variables, bean-properties, bean-methods

bean-properties

Prerequisites
Architecture
Solution
Creating the Maven project
Constraints
JSON mapping and validation
REST end point validation
Service method validation
A frontend
Run the application
Going further
Limitations
- META-INF/validation.xml
- ValidatorFactory and native executables
Hibernate Validator Configuration Reference