Javax validation not working on boot rest controller parameter - spring

Question

I have a Pojo (annotated with Lombok if it makes any difference) and a RestController in a Spring Boot app. The pojo method parameter is annotated with #Valid yet there is no validation applied and even if I add a BindingResult second parameter, it never has any error. I'm testing this with Swagger UI, posting a JSON, but I don't see why that would make any differnce... Did I miss something obvious?
import lombok.Builder;
import lombok.Data;
import lombok.EqualsAndHashCode;
import lombok.experimental.Tolerate;
import org.springframework.data.mongodb.core.mapping.Document;
import javax.validation.constraints.NotBlank;
#Data
#EqualsAndHashCode(callSuper = true)
#Builder
public class MyPojo extends GenericDocument {
#NotBlank
private String name;
#Tolerate
public MyPojo() {
}
}
import javax.validation.Valid;
#RestController
#RequestMapping(value = "/myUrl", produces = APPLICATION_JSON_VALUE)
public class MyController {
#PostMapping
public ResponseEntity<MyPojo> createNew(#RequestBody #Valid MyPojo pojo){...
}
}
Solution
Adding this dependency was enough:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
It is strange that adding javax.validation:validation-api and org.hibernate:hibernate-validator was not enough despite the documentation

Answer 1

You should try adding Spring’s #Validated annotation to the controller at class level to tell Spring to evaluate the constraint annotations on method parameters.
Example:
#Slf4j
#Validated
#RestController
#RequestMapping(value = "/myUrl", produces = APPLICATION_JSON_VALUE)
public class MyController {
#PostMapping
public ResponseEntity<MyPojo> createNew(#RequestBody #Valid MyPojo pojo){...
}
}
This org.springframework.validation.annotation.Validated annotation can be applied at both class level and method or parameter level.

Answer 2

Per the documentation, which is not entirely clear, you need to have a JSR-303 validation provider such as Hibernate Validator (docs here) on your classpath so Spring can detect and use it.
It also seems in some cases you may need the Spring Boot Starter Validation dependency (spring-boot-starter-validation) on your classpath as well. I would suggest trying that to see if it helps. (Strangely, though, I don't see that detailed in the Spring docs - just briefly mentioned here.)
Or you could maybe implement the Validator interface as per here, but not sure.