I've tried everything here but nothing worked so I copied the pom.xml which is actually working there I found that we have to add this configuration after build tag. Then compile and it will generate Mapper Impl class in target folder

<repositories>
    <repository>
        <id>spring-milestones</id>
        <name>Spring Milestones</name>
        <url>https://repo.spring.io/milestone</url>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
        </repository>
</repositories>