Spring invoke BeanFactoryPostProcessors with explicit order

BeanFactoryPostProcessor may implement interface Ordered or not , for example: CachingMetadataReaderFactoryPostProcessor, ConfigurationWarningsPostProcessor.

If we want to invoke them by order, we need sorting, otherwise the order is depends on the order of their owner ApplicationContextInitializer:

the caller:

    protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
        PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());
                // some code
    }

class SharedMetadataReaderFactoryContextInitializer
        implements ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered {
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        BeanFactoryPostProcessor postProcessor = new CachingMetadataReaderFactoryPostProcessor(applicationContext);
        applicationContext.addBeanFactoryPostProcessor(postProcessor);
    }

    @Override
    public int getOrder() {
        return 0;
    }

    static class CachingMetadataReaderFactoryPostProcessor
            implements BeanDefinitionRegistryPostProcessor, PriorityOrdered {
        @Override
        public int getOrder() {
            // Must happen before the ConfigurationClassPostProcessor is created
            return Ordered.HIGHEST_PRECEDENCE;
        }
        }
}

public class ConfigurationWarningsApplicationContextInitializer
        implements ApplicationContextInitializer<ConfigurableApplicationContext> {
    @Override
    public void initialize(ConfigurableApplicationContext context) {
        context.addBeanFactoryPostProcessor(new ConfigurationWarningsPostProcessor(getChecks()));
    }

    protected static final class ConfigurationWarningsPostProcessor
            implements PriorityOrdered, BeanDefinitionRegistryPostProcessor {

        @Override
        public int getOrder() {
            return Ordered.LOWEST_PRECEDENCE - 1;
        }
}