Force @Autowired spring boot and webFlux

Question

My application use spring boot and webflux with tomcat embedded.

I use a 3rd library that contains some servlet listeners.

A listener property injector of BagServletContextListener returns null when the app is started.

@WebListener
public class BagServletContextListener implements ServletContextListener {
    @Autowired
    private BagInjector injector;

    @Override
    public void contextInitialized(ServletContextEvent event) {
        this.injector.inject();

    }
}

How can I force initialization of this component through @bean or other way?

a piece of my pom.xml

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>

Note: The packaging of app is a war.

The lack of initialization of this component cause null pointer exception in contextInitialized method.

[ERROR ] SRVE0283E: Exception caught while initializing context: java.lang.NullPointerException at com.devIo.ee.BagServletContextListener.contextInitialized(BagServletContextListener.java:33) at com.ibm.ws.webcontainer.webapp.WebApp.notifyServletContextCreated(WebApp.java:2391) at [internal classes]

Answer 1

You have not told Spring Boot to scan your BagServletContextListener class. The @WebListener does not accomplish that.

Add @ServletComponentScan to your SpringBootApplication class to ensure the BagInjector is scanned - and Spring knows how to autowire it for you.

Like this:

@ServletComponentScan
@SpringBootApplication
public class SpringBootApp {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootApp.class, args);
    }

}