Are all Spring Framework Java Configuration injection examples buggy

Question

I m wondering if it s only me or are most examples of Spring s Java Configuration flawed  Like here for example   http   spring io blog 2008 03 27 spring-java-configuration-what-s-new-in-m3  http   spring io blog 2013 07 18 javaconfig-support-in-the-spring-tool-suite  Notice how they inject beans  They use methods directly  like  new OrderRepository dataSource    here    Configuration public class ApplicationConfig        public  Bean OrderRepository orderRepository             return new OrderRepository dataSource                public  Bean DataSource dataSource                instantiate and return an new DataSource               This got me thinking - wouldn t it create two objects if used twice  Effectively bypassing singleton guarantee of Spring  Why aren t they injecting beans instead  As dependency framework was designed to work in the first place   Let s do a quick test  Take those two classes for example - TestParent and TestedChild  Parent accepts a child  new TestParent new TestedChild     We will make them singleton beans in a minute   public class TestedChild      public class TestParent        private TestedChild child       public TestParent TestedChild child            this child   child             public TestedChild getChild     return child         What I want to see is if we can in fact get two different instances of TestedChild created during context initialization  Let s configure our singleton beans now    Configuration public class TestInjectionConfig         Bean name    injected       public TestParent injected TestedChild bean            return new TestParent bean               Bean name    direct       public TestParent direct             return new TestParent testedBean                 Bean     public TestedChild testedBean             return new TestedChild               I m creating two different TestParent objects which should have the same TestedChild injected at the time of their creation    Let s test them    RunWith SpringJUnit4ClassRunner class   ContextConfiguration classes   TestInjectionConfig class  public class InjectionApplicationTest         Inject  Named  injected       TestParent injected        Inject  Named  direct       TestParent direct        Test     public void instancesShouldBeTheSame              Assert assertSame injected  direct               I would expect the beans to be the same but this is what I m getting on Spring 3 2 6   junit framework AssertionFailedError  expected same  lt pl aie TestParent 59e5a42c gt  was not  lt pl aie TestParent 737d72cf gt    Back to the question  Why are the examples using direct method calls on Spring configuration classes  And if they are meant to be called like that  why are they annotated with a  Bean annotation  Is it a bad practice or is my logic code flawed somewhere

User · Accepted Answer

In your test  you are comparing the two TestParent beans  not the single TestedChild bean   Also  Spring proxies your  Configuration class so that when you call one of the  Bean annotated methods  it caches the result and always returns the same object on future calls   See here    How does Spring  Configuration cache references to beans

[java] Are all Spring Framework Java Configuration injection examples buggy?

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