Spring @Autowired beans are null - how to find the mistake

Question

I integrated Spring batch and the quartz timer into my Spring-MVC application. Currently I have several directories:

@Autowire works everywhere but in MyBatchJob.java (-> code compiles but properties are NULL during runtime)

- batch
    +- MyProcessor
    +- MyReader
    +- MyWriter
    +- MyListener
- config
    +- MainConfig
    +- BatchConfig
- controller
[...]
- schedule
    +- MyBatchJob

BatchConfig is annotated with:

@Configuration
@ComponentScan(basePackages = "my.backend.schedule")
@EnableBatchProcessing // imports jobLauncher, stepBuilderFactory, jobBuilderFactory, ...
public class BatchConfig {

    @Bean
    public JobDetail jobDetail() {
        return newJob(MyBatchJob.class)
            .withIdentity("name", "group")
            .build();
    }

and imported in MainConfig using @Import(BatchConfig.class). In this configuration file and in the controllers I can @Autowire the classes I need. But it does not work in my my.backend.schedule.MyBatchJob class:

@Component
public class MyBatchJob implements org.quartz.Job {

    @Autowired
    JobLauncher jobLauncher; // null

    @Autowired
    StepBuilderFactory stepBuilderFactory; // null

    @Autowired
    JobBuilderFactory jobBuilderFactory; // null

What is the reason for this, how can I find and fix it?

Meta: I already searched a lot and saw many threads here on SO - but did not find the solution. I already know how the spring beans live inside the container but that does not give me the answer - I may overlook something.

edit: additional information as requested inserted into BatchConfig class above.

edit2: Changing to JobDetailFactoryBean:

BatchConfig:

@Bean
public JobDetailFactoryBean jobDetailFactory() {
    JobDetailFactoryBean factory = new JobDetailFactoryBean();
    factory.setJobClass(MyBatchJob.class);
    return factory;
}

@Bean
public Trigger myJobTrigger() throws Exception {

    SchedulerFactory schedulerFactory = new StdSchedulerFactory();
    Scheduler scheduler = schedulerFactory.getScheduler();
    scheduler.start();

    Trigger trigger = newTrigger()
            .withIdentity("mySynchTrigger", "synch")
            .startNow()
            .withSchedule(simpleSchedule()
                .withIntervalInSeconds(30) // testing
                .repeatForever())
            .build();
    scheduler.scheduleJob(jobDetailFactory().getObject(), trigger);
    return trigger;
}

Inside the BatchConfig I create a `JobDetail`-Bean using `JobBuilder.newJob`. Could this be the issue? — dexBerlin, Dec 23 '14 at 14:22
yes. you should always use @Autowired for all beans. new operator will cause issues to autowired — Sushant Tambare, Dec 23 '14 at 14:24
I do not use the new operator but the JobBuilder.newJob method of the quartz framework returning a static JobBuilder. — dexBerlin, Dec 23 '14 at 14:29
Better than an own word explanation: http://quartz-scheduler.org/api/2.2.0/org/quartz/JobBuilder.html — dexBerlin, Dec 23 '14 at 14:35
http://stackoverflow.com/questions/6990767/inject-bean-reference-into-a-quartz-job-in-spring — Alan Hay, Dec 23 '14 at 14:36
I suspect a different instance is being used. Instantiating with `new` isn't a problem for an `@Bean`; Spring autowires them. — chrylis -cautiouslyoptimistic-, Dec 23 '14 at 15:40
The `JobDetailFactoryBean` creates a new instance of `MyBatchJob`. It doesn't use the Spring bean. Why don't you just use `@Scheduled` instead of this rather complex setup? — a better oliver, Dec 24 '14 at 08:45

score 0 · Answer 1 · answered Dec 23 '14 at 14:37

0

You should register a JobDetailFactoryBean as described here rather than using the Quartz API yourself.

answered Dec 23 '14 at 14:37

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I changed the BatchConfig as in the question above (using the JobDetailFactoryBean), jobLauncher still remains NULL. Maybe the documentation is outdated as it is still xml only? – dexBerlin Dec 23 '14 at 15:15

Spring @Autowired beans are null - how to find the mistake

1 Answers1