How to create additional TaskExecutor beside TaskExecutionAutoConfiguration?

Question

I want spring to load the default ThreadPoolTaskExecutor from TaskExecutionAutoConfiguration. Though I want to provide may own additional executor for some explicit side-tasks:

@Bean
public ThreadPoolExecutor myRequestPool() {
    return (ThreadPoolExecutor) Executors.newFixedThreadPool(10);
}

Problem: adding the bean above, the TaskExecutionAutoConfiguration will not be executed anymore, and the spring-default executor will not be initialized, because @ConditionalOnMissingBean(Executor.class) does not match anymore:

package org.springframework.boot.autoconfigure.task;

public class TaskExecutionAutoConfiguration {

    @Lazy
    @Bean(name = APPLICATION_TASK_EXECUTOR_BEAN_NAME)
    @ConditionalOnMissingBean(Executor.class)
    public ThreadPoolTaskExecutor applicationTaskExecutor(TaskExecutorBuilder builder) {
        return builder.build();
    }

Question: how can I still let spring create both beans?

Answer 1

The executor bean in TaskExecutionAutoConfiguration will only be created if no other executor beans exist (due to @ConditionalOnMissingBean(Executor.class)) at the moment when processing that auto-configuration . So , in order to create both of our executor and the one defined in TaskExecutionAutoConfiguration , we need to make sure our bean is processed after TaskExecutionAutoConfiguration

According to docs , if we make our bean to be the auto-configuration candidates (which requires adding the @Configuration class in META-INF/spring.factories), we can then use @AutoConfigureAfter to configure it to be processed after TaskExecutionAutoConfiguration :

package foo.bar.baz.qux;

@Configuration
@AutoConfigureAfter(TaskExecutionAutoConfiguration.class)
public class Config {
    @Bean
    public ThreadPoolExecutor myRequestPool() {
        return (ThreadPoolExecutor) Executors.newFixedThreadPool(10);
    }
}

Then create META-INF/spring.factories which contains :

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  foo.bar.baz.qux.Config