Spring Batch - My Batch seems executing two steps at the same time?

Question

I can't really understand what's going on. I'm studying Spring Batch and I'd like to execute two steps for some reasons, one after the other.

Now please don't mind what the steps are currently doing, just keep in mind that I would like to perform two steps sequentially.

This is the code:

@Configuration
@EnableBatchProcessing
public class JobConfiguration {
    @Autowired
    private JobBuilderFactory jobBuilderFactory;

    @Autowired
    private StepBuilderFactory stepBuilderFactory;
    
    private List<Employee> employeesToSave = new ArrayList<Employee>();


    public JsonItemReader<Employee> jsonReader() {

        
        System.out.println("Try to read JSON");
        
        final ObjectMapper mapper = new ObjectMapper();

        final JacksonJsonObjectReader<Employee> jsonObjectReader = new JacksonJsonObjectReader<>(
                Employee.class);
        jsonObjectReader.setMapper(mapper);

        return new JsonItemReaderBuilder<Employee>().jsonObjectReader(jsonObjectReader)
                .resource(new ClassPathResource("input.json"))
                .name("myReader")
                .build();

    }
    

    public ListItemReader<Employee> listReader() {
        
        System.out.println("Read from list");
        
        return new ListItemReader<Employee>(employeesToSave);

*/
    }
    

    public ItemProcessor<Employee,Employee> filterProcessor() {
        return employee -> {
            
            System.out.println("Processing JSON");
            
            return employee;
        };
    }

    public ItemWriter<Employee> filterWriter() {

        return listEmployee -> {
            
            employeesToSave.addAll(listEmployee);
            System.out.println("Save on list " + listEmployee.toString());
                        
        };

    }

    public ItemWriter<Employee> insertToDBWriter() {

        System.out.println("Try to save on DB");
        return listEmployee -> {

            System.out.println("Save on DB " + listEmployee.toString());
                        
        };

    }

    public Step filterStep() {
        
        StepBuilder stepBuilder = stepBuilderFactory.get("filterStep");
        SimpleStepBuilder<Employee, Employee> simpleStepBuilder = stepBuilder.chunk(5);
        return simpleStepBuilder.reader(jsonReader()).processor(filterProcessor()).writer(filterWriter()).build();
    }

    public Step insertToDBStep() {
        
        StepBuilder stepBuilder = stepBuilderFactory.get("insertToDBStep");
        SimpleStepBuilder<Employee, Employee> simpleStepBuilder = stepBuilder.chunk(5);
        return simpleStepBuilder.reader(listReader()).writer(insertToDBWriter()).build();
    }

    @Bean
    public Job myJob(JobRepository jobRepository, PlatformTransactionManager platformTransactionManager) {

        return jobBuilderFactory.get("myJob").incrementer(new RunIdIncrementer())
                .start(filterStep())
                .next(insertToDBStep())
                .build();
    }
}

Why doesn't the insertToDBStep starts at the end of the filterStep and it actually looks like the filter is running at the same time? And why it looks like the job starts after the initialization of Root WebApplicationContext?

This is the output.

2022-05-23 15:40:49.418  INFO 14008 --- [  restartedMain] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1024 ms
Try to read JSON
Read from list
Try to save on DB
2022-05-23 15:40:49.882  INFO 14008 --- [  restartedMain] o.s.b.d.a.OptionalLiveReloadServer       : LiveReload server is running on port 35729
2022-05-23 15:40:49.917  INFO 14008 --- [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2022-05-23 15:40:49.926  INFO 14008 --- [  restartedMain] c.marco.firstbatch.TestBatchApplication  : Started TestBatchApplication in 1.985 seconds (JVM running for 2.789)
2022-05-23 15:40:49.927  INFO 14008 --- [  restartedMain] o.s.b.a.b.JobLauncherApplicationRunner   : Running default command line with: []
2022-05-23 15:40:49.928  WARN 14008 --- [  restartedMain] o.s.b.c.c.a.DefaultBatchConfigurer       : No datasource was provided...using a Map based JobRepository
2022-05-23 15:40:49.928  WARN 14008 --- [  restartedMain] o.s.b.c.c.a.DefaultBatchConfigurer       : No transaction manager was provided, using a ResourcelessTransactionManager
2022-05-23 15:40:49.943  INFO 14008 --- [  restartedMain] o.s.b.c.l.support.SimpleJobLauncher      : No TaskExecutor has been set, defaulting to synchronous executor.
2022-05-23 15:40:49.972  INFO 14008 --- [  restartedMain] o.s.b.c.l.support.SimpleJobLauncher      : Job: [SimpleJob: [name=myJob]] launched with the following parameters: [{run.id=1}]
2022-05-23 15:40:50.003  INFO 14008 --- [  restartedMain] o.s.batch.core.job.SimpleStepHandler     : Executing step: [filterStep]
Processing JSON
Processing JSON
Processing JSON
Processing JSON
Processing JSON
Save on list [com.marco.firstbatch.Employee@958d6e7, com.marco.firstbatch.Employee@464d17f8, com.marco.firstbatch.Employee@705520ac, com.marco.firstbatch.Employee@1a9f8e93, com.marco.firstbatch.Employee@55bf8cc9]
Processing JSON
Processing JSON
Save on list [com.marco.firstbatch.Employee@55d706c0, com.marco.firstbatch.Employee@1bc46dd4]
2022-05-23 15:40:50.074  INFO 14008 --- [  restartedMain] o.s.batch.core.step.AbstractStep         : Step: [filterStep] executed in 70ms
2022-05-23 15:40:50.081  INFO 14008 --- [  restartedMain] o.s.batch.core.job.SimpleStepHandler     : Executing step: [insertToDBStep]
2022-05-23 15:40:50.084  INFO 14008 --- [  restartedMain] o.s.batch.core.step.AbstractStep         : Step: [insertToDBStep] executed in 3ms
2022-05-23 15:40:50.088  INFO 14008 --- [  restartedMain] o.s.b.c.l.support.SimpleJobLauncher      : Job: [SimpleJob: [name=myJob]] completed with the following parameters: [{run.id=1}] and the following status: [COMPLETED] in 96ms

Thanks in advance.