I need to use @ExtensionMethod but I have “cannot find symbol” for extension methods when I compile project.

spring boot, java 11

for example I have:

import lombok.experimental.ExtensionMethod;

@SuppressWarnings("checkstyle:MissingJavadocMethod")
@ExtensionMethod(TestUtility.class)
public class TestUtility {

    public static String test(String a) {
        return a.toLowerCase().test2();
    }

    public static String test2(String a) {
        return a.toUpperCase();
    }
}

and I get compile error for return a.toLowerCase().test2();:

tried with different maven-compiler-plugin and lombok versions

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.7.0</version>
                <configuration>
                    <source>11</source>
                    <target>11</target>
                    <annotationProcessorPaths>
                        <path>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                            <version>1.18.34</version>
                        </path>
                        <path>
                            <groupId>org.mapstruct</groupId>
                            <artifactId>mapstruct-processor</artifactId>
                            <version>${mapstruct.version}</version>
                        </path>
                    </annotationProcessorPaths>
                </configuration>
            </plugin>