The all-open plugin for Maven can be used as follows:

    <plugin>
        <artifactId>kotlin-maven-plugin</artifactId>
        <groupId>org.jetbrains.kotlin</groupId>
        <version>${kotlin.version}</version>
        <configuration>
            <compilerPlugins>
                <plugin>all-open</plugin>
            </compilerPlugins>
            <pluginOptions>
               <option>all-open:all-open:annotation=javax.inject.Inject</option>
               <option>all-open:annotation=all-open:annotation=javax.ejb.Stateless</option>
            </pluginOptions>
        </configuration>
        <dependencies>
            <dependency>
                <groupId>org.jetbrains.kotlin</groupId>
                <artifactId>kotlin-maven-allopen</artifactId>
                <version>${kotlin.version}</version>
            </dependency>
        </dependencies>
    </plugin>