Order of bean initialization in Spring

Question

I have the following beans in my Spring config file:

<bean id="myList" class="java.util.ArrayList">
    <constructor-arg>
        <list>
            <ref bean="elem1"/>
            <ref bean="elem2"/>
            <ref bean="elem3"/>
            <ref bean="elem4"/>     
        </list>
    </constructor-arg>
</bean>
<bean id="elem4" class="myClass">
    <property name="title" value="random4"/>
</bean>
<bean id="elem1" class="myClass">
    <property name="title" value="random1"/>
</bean>
<bean id="elem3" class="myClass">
    <property name="title" value="random3"/>
</bean>
<bean id="elem2" class="myClass">
    <property name="title" value="random2"/>
</bean>

I have noticed that in my application the elements in myList are in the following order: elem4, elem1, elem3, elem2. I was expecting that the elements in my list will be in the order I set when I declared the ref beans ( elem1, elem2, elem3, elem4). Is there an order in which Spring initializes beans? Is there a way I can specify an order for the elements in my list?

Try to defined beans creation in the order you like ie. `` etc — MaxZoom, Aug 20 '15 at 14:46
Thanks for your answer. I was thinking about that, but i was wondering why Spring behaves like that. The beans (elem4, elem1, elem3, elem2) are initialized first because the list depends on them, but why the list is not populated in the order of the ref beans. — Roxana, Aug 20 '15 at 14:53
see this similar question http://stackoverflow.com/q/3187899/3166303 — leeor, Aug 20 '15 at 14:53
Do you mean that the beans are initialized in the order 4132 or that the list is [ bean4, bean1, bean3, bean2 ] in that order ? The first is normal, the second not. — Serge Ballesta, Aug 20 '15 at 15:22
The order of the list [ bean4, bean1, bean3, bean2 ] seems strange to me. — Roxana, Aug 21 '15 at 06:20
I tried this with Spring 4 and the list order is 1,2,3,4 as expected. — jaco0646, Aug 21 '15 at 19:45

score 0 · Answer 1 · answered Oct 08 '15 at 11:47

The spring does respect the order you gave in the list. The elements in the list would exactly be the [elem1,elem2,elem3,elem4] as you specified. Otherwise, you are doing something wrong, can you show the code which prints you the different order?

The order of bean initialization however may be different and depends on bean dependencies, so, for example if you have two beans

<bean id="holder" class="my.HolderBean" lazy-init="false">
   <property name="inner" ref="inner"/>
</bean>
<bean id="inner" class="my.InnerBean" lazy-init="false"/>

Then regardless of the xml definition order, the InnerBean will be initialized first, then during HolderBean initialization it will be injected into HolderBean.

Order of bean initialization in Spring

1 Answers1