Spring Cannot inject generic FactoryBean

Here is an example test case:

import org.junit.Test;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.core.ResolvableType;

import static org.junit.Assert.assertTrue;

public class FactoryTests {

    @Test
    public void testAutowire() {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
                TestConfig.class);
        ClassWithGenericBar classWithGenericBar = context.getBean(ClassWithGenericBar.class);
        assertTrue(classWithGenericBar.stringGenericBar.type.equals(String.class));
    }

    @Test
    public void testGetByType() {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(
                TestConfig.class);
        String[] names = context.getBeanNamesForType(ResolvableType.forClassWithGenerics(GenericBar.class, String.class));
        assertTrue(names.length > 0);
    }

    static class TestConfig {

        @Bean
        GenericBarFactory<String> stringGenericBarFactory() {
            return new GenericBarFactory<>(String.class);
        }

        @Bean
        GenericBarFactory<Integer> integerGenericBarFactory() {
            return new GenericBarFactory<>(Integer.class);
        }

        @Bean
        ClassWithGenericBar classWithGenericBar() {
            return new ClassWithGenericBar();
        }
    }

    public static class GenericBar<T> {
        Class<T> type;

        public GenericBar(Class<T> type) {
            this.type = type;
        }
    }

    public static class GenericBarFactory<T> implements FactoryBean<GenericBar<T>> {

        private Class<T> type;

        public GenericBarFactory(Class<T> type) {
            this.type = type;
        }

        @Override
        public GenericBar<T> getObject() {
            return new GenericBar<>(type);
        }

        @Override
        public Class<?> getObjectType() {
            return type;
        }
    }

    public static class ClassWithGenericBar {
        @Autowired
        GenericBar<String> stringGenericBar;

        @Autowired
        GenericBar<Integer> integerGenericBar;
    }

}

And I got exception:

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.guice.FactoryTests$GenericBar<java.lang.String>' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1695)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1253)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:636)
    ... 36 more

Is this an expected behavior or a bug?

Comment From: snicoll

The object type exposed by your FactoryBean is the type argument. So, looking at your example, you expose that the first factory bean exposes a String and the second one exposes an Integer. There is no link between GenericBarFactory<String> and GenericBar<String> so it makes sense the injection there doesn't work.