The bean validation api is on the classpath but no implementation could be found

When you encounter the error message “The Bean Validation API is on the classpath but no implementation could be found,” it means that the necessary implementation of the Bean Validation API is missing from your project. The Bean Validation API provides a set of annotations and interfaces for defining constraints on Java objects, and it requires an implementation to actually enforce those constraints.

To resolve this issue, you need to add a Bean Validation implementation to your project’s dependencies. The most commonly used implementation is Hibernate Validator, which is the reference implementation of the Bean Validation API. Here’s an example of how you can add Hibernate Validator as a dependency using Maven:

        <dependencies>
            <dependency>
                <groupId>org.hibernate.validator</groupId>
                <artifactId>hibernate-validator</artifactId>
                <version>${hibernate-validator.version}</version>
            </dependency>
        </dependencies>
    

In this example, the groupId is “org.hibernate.validator” and the artifactId is “hibernate-validator”. The version “${hibernate-validator.version}” should be replaced with the specific version you want to use, for example, “6.1.6.Final”.

After adding the Bean Validation implementation to your project, make sure to rebuild and redeploy it. The error message should no longer appear, and you should be able to use the Bean Validation API and its annotations in your code.