Kotlin JSR303 Bean Validation doesn’t work from Springboot version 2.3.0.RELEASE onwards

Question

Recently working on a project I noticed that JSR303 Bean Validation doesn’t work from Springboot version 2.3.0.RELEASE onwards (at least, not in the same way, and I couldn’t figure out what changed even from release doc https://spring.io/blog/2020/05/15/spring-boot-2-3-0-available-now) for Kotlin.

Issue: The bean annotations like @NotNull, @NotBlank, etc are ignored and validation doesn’t kick in.

Has someone noticed something similar or have any idea what changed and how to make bean validation work with Springboot 2.3.0.RELEASE onwards?

here was my setup-

Working setup

data class HelloDto(

@field:NotBlank(message = "greeting is required")
val greeting: String,

@field:NotBlank(message = "count is Required")
val count: String
)

@RestController
@RequestMapping("/api")
class MyController {

    @PostMapping("/hello")
    fun helloKotlin(@RequestBody @Valid helloDto: HelloDto): String {
        return "hello world "+ helloDto.greeting
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.13.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>demo</description>
    <properties>
        <java.version>11</java.version>
        <kotlin.version>1.5.31</kotlin.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>javax.validation</groupId>
            <artifactId>validation-api</artifactId>
            <version>2.0.1.Final</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.2.13.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-reflect</artifactId>
        </dependency>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-stdlib-jdk8</artifactId>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.module</groupId>
            <artifactId>jackson-module-kotlin</artifactId>
            <version>2.13.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springdoc</groupId>
            <artifactId>springdoc-openapi-ui</artifactId>
            <version>1.6.2</version>
        </dependency>

    </dependencies>

    <build>
        <sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
        <testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.jetbrains.kotlin</groupId>
                <artifactId>kotlin-maven-plugin</artifactId>
                <configuration>
                    <args>
                        <arg>-Xjsr305=strict</arg>
                    </args>
                    <compilerPlugins>
                        <plugin>spring</plugin>
                    </compilerPlugins>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>org.jetbrains.kotlin</groupId>
                        <artifactId>kotlin-maven-allopen</artifactId>
                        <version>${kotlin.version}</version>
                    </dependency>
                </dependencies>
            </plugin>
            <plugin>
                <groupId>org.openapitools</groupId>
                <artifactId>openapi-generator-maven-plugin</artifactId>
                <!-- RELEASE_VERSION -->
                <version>5.1.0</version>
                <!-- /RELEASE_VERSION -->
                <executions>
                    <execution>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <inputSpec>${project.basedir}/src/main/resources/bank-api.yaml</inputSpec>
                            <generatorName>java</generatorName>
                            <configOptions>
                                <sourceFolder>src/gen/java/main</sourceFolder>
                            </configOptions>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

Request:

{
  "name":"",
  "count":""
}

Response:

{
    "timestamp": "2021-12-23T16:18:03.177+0000",
    "status": 400,
    "error": "Bad Request",
    "errors": [
        {
            "codes": [
                "NotBlank.user.name",
                "NotBlank.name",
                "NotBlank.java.lang.String",
                "NotBlank"
            ],
            "arguments": [
                {
                    "codes": [
                        "user.name",
                        "name"
                    ],
                    "arguments": null,
                    "defaultMessage": "name",
                    "code": "name"
                }
            ],
            "defaultMessage": "must not be blank",
            "objectName": "user",
            "field": "name",
            "rejectedValue": "",
            "bindingFailure": false,
            "code": "NotBlank"
        }
    ],
    "message": "Validation failed for object='user'. Error count: 1",
    "path": "/users"
}

Non Working setup - As soon as I updated springboot to 2.3.0.RELEASE the validations were ignored.

Response:

There are 2 reasons why I posted this question -

1. To get some help finding out what changed.
2. To help others not waste so much time due to version issues (I spend a day to find this out)

TIA!