Spring Custom ImportBeanDefinitionRegistrar with CustomClassLoader failed

Affects: \<5.2.11.RELEASE>

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For enhancements, provide context and describe the problem. Some of my java lib not imported by maven, and I want to load it by CustomClassLoader, and scan java lib class to register spring bean.

I found to implements ImportBeanDefinitionRegistrar and @Import it will good for me. some code like this:

   @Configuration(proxyBeanMethods = false)
    static class PluginBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {

        @Override
        public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
           ClassLoader pluginClassLoader = Plugin.getPluginClassLoader();
          //scanner
          ClassPathBeanDefinitionScanner scanner =
                  new PluginClassPathBeanDefinitionScanner(registry, true, applicationContext.getEnvironment(),
                          new DefaultResourceLoader(pluginClassLoader));
          BeanDefinition bd = BeanDefinitionBuilder.genericBeanDefinition(Plugin.getPluginClass()).getBeanDefinition();

          Set<String> basePackages = new LinkedHashSet<>();
          basePackages.add(ClassUtils.getPackageName(Plugin.getPluginClass()));

          scanner.addExcludeFilter(new AssignableTypeFilter(TypeExcludeFilter.class));
          scanner.addExcludeFilter(new AssignableTypeFilter(AutoConfigurationExcludeFilter.class));
          scanner.addExcludeFilter(new AnnotationTypeFilter(SpringBootApplication.class));

          scanner.scan(StringUtils.toStringArray(basePackages));
        }
    }

and PluginClassPathBeanDefinitionScanner will load class Resource into BeanDefinition

public class PluginClassPathBeanDefinitionScanner extends ClassPathBeanDefinitionScanner {

    @SneakyThrows
    @Override
    public int scan(String... basePackages) {
        int beanCountAtScanStart = this.getRegistry().getBeanDefinitionCount();

        Set<BeanDefinitionHolder> scanBds = doScan(basePackages);
        loadBeanResource(scanBds);

        return (this.getRegistry().getBeanDefinitionCount() - beanCountAtScanStart);
    }

    private void loadBeanResource(Set<BeanDefinitionHolder> bdhs) throws IOException {
        for (BeanDefinitionHolder bdh : bdhs) {
            BeanDefinition bd = bdh.getBeanDefinition();
            if (bd instanceof AbstractBeanDefinition) {
                //load class by this resource loader
                MetadataReader meta = this.getMetadataReaderFactory().getMetadataReader(Objects.requireNonNull(bd.getBeanClassName()));
                ((AbstractBeanDefinition) bd).setResource(meta.getResource());
            }
        }
    }
}

unfortunately SpringContext org.springframework.context.annotation.ConfigurationClassParser#parse(java.util.Set<org.springframework.beans.factory.config.BeanDefinitionHolder>) will parse those loaded BeanDefinitions with SpringContext org.springframework.context.annotation.ConfigurationClassParser#metadataReaderFactory and absolutely ClassNotFound Exception.

What if: * first use BeanDefinition Resource or BeanClass if it is not null * or load resource or bean class by SpringContext ResourceLoad(or MetadataReaderFactory)

If there are another way to solve my problem, please let me know, thanks!!!