Spring in Action Chapter 2 changing XML bean to JavaConfig doesn't pass the test

Question

Below is my Bean configuration code, but the configuration doesn't pass the test as it says it failed to load ApplicationContext. Is there something I'm doing wrong? I added @Autowire to methods of each class that's needed (except for interface method), but I still have no idea why it's not loading

package soundsystems;

import java.util.ArrayList;
import java.util.List;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class CDPlayerConfig 
{
    @Bean
    public CompactDisc sgtPeppers()
    {
        return new SgtPeppers();
    }

    @Bean(name = "SgtPepperPlayer")
    public CDPlayer cdPlayer()
    {
        return new CDPlayer(sgtPeppers());
    }

    @Bean(name = "AnyCDPlayer")
    public CDPlayer cdPlayer(CompactDisc cd)
    {
        return new CDPlayer(cd);
    }

    @Bean
    public BlankDisc reallyBlankDisc()
    {
        return new BlankDisc();
    }

    @Bean
    public BlankDisc blankDisc()
    {
        BlankDisc bd = new BlankDisc();

        String title = "Sgt. Pepper's Lonely Hearts Club Band";
        String artist = "The Beatles";

        List<String> tracks = new ArrayList<String>();
        tracks.add("Sgt. Pepper's Lonely Hearts Club Band");
        tracks.add("With a Little Help from My Friends");
        tracks.add("Lucy in the Sky with Diamonds");
        tracks.add("Getting Better");
        tracks.add("Fixing a Hole");

        bd.setTitle(title);
        bd.setArtist(artist);
        bd.setTracks(tracks);

        return bd;
    }

    @Bean
    public Discography beatlesDiscography()
    {
        Discography dg = new Discography();

        String artist = "The Beatles";
        CompactDisc SgtPeppers = new SgtPeppers();
        CompactDisc WhiteAlbum = new WhiteAlbum();
        CompactDisc HardDaysNight = new HardDaysNight();
        CompactDisc Revolver = new Revolver();

        List<CompactDisc> cds = new ArrayList<CompactDisc>();
        cds.add(SgtPeppers);
        cds.add(WhiteAlbum);
        cds.add(HardDaysNight);
        cds.add(Revolver);

        dg.setArtist(artist);
        dg.setCDs(cds);     

        return dg;
    }

}



package soundsystems;

import static org.junit.Assert.*;

import org.junit.Rule;
import org.junit.Test;
import org.junit.contrib.java.lang.system.SystemOutRule;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = CDPlayerConfig.class)
public class CDPlayerTest 
{
    @Rule
    public final SystemOutRule log = new SystemOutRule().enableLog();

    @Autowired
    private CompactDisc cd;

    @Autowired
    private MediaPlayer player;

    @Test
    public void cdShouldNotBeNull()
    {
        assertNotNull(cd);
    }

    @Test
    public void play()
    {
        player.play();
        assertEquals("Playing Sgt. Pepper's Lonely Hearts Club Band" + " by The Beatles\n", log.getLog());
    }
}

Thanks for having a look.

edit: Error

    java.lang.IllegalStateException: Failed to load ApplicationContext
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124)
    at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:228)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:230)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:249)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'AnyCDPlayer': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void soundsystems.CDPlayer.setCompactDisc(soundsystems.CompactDisc); nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [soundsystems.CompactDisc] is defined: expected single matching bean but found 3: blankDisc,sgtPeppers,reallyBlankDisc
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:125)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60)
    at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:109)
    at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:261)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98)
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116)
    ... 25 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void soundsystems.CDPlayer.setCompactDisc(soundsystems.CompactDisc); nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [soundsystems.CompactDisc] is defined: expected single matching bean but found 3: blankDisc,sgtPeppers,reallyBlankDisc
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:661)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331)
    ... 41 more
Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [soundsystems.CompactDisc] is defined: expected single matching bean but found 3: blankDisc,sgtPeppers,reallyBlankDisc
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1126)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:618)
    ... 43 more

Answer 1

I believe that Spring's @Autowired default mode is by type. It means that Spring will try to autowire bean by interface type, btw you have 3 beans with same interface and Spring got confused which one to choose. If you want to achieve autowiring by name you should use @Qualifier : @Qualifier("beanname")

Answer 2

The error is quite clear:

Could not autowire method: public void soundsystems.CDPlayer.setCompactDisc(soundsystems.CompactDisc); 
nested exception is 
org.springframework.beans.factory.NoUniqueBeanDefinitionException: 
No qualifying bean of type [soundsystems.CompactDisc] is defined: 
expected single matching bean but found 3: blankDisc,sgtPeppers,reallyBlankDisc

You annotated you setCompactDisc() method in CDPlayer with @Autowired, so Spring tries to call it with a bean of type CompactDisc, but it has 3 of them, and thus can't decide which one to inject. Don't annotate this method with Autowired. Or even better, remove that method, since the CompactDisc is already initialized by the constructor.