Injecting Null

In the last posts we saw Springs ability to inject collections - both simple value types and complex object types. But just because Spring allows us to configure objects does not mean we have to always configure them. For e.g. there could be a Singer class that uses constructor injection to wire its "song" property. But what do you do if you don't have a song ?

Injecting Collections of Objects

In the previous post we saw how to inject a collection of values. However Spring is not limited to only wiring primitive values . It allows us to create collections of beans and wire them into other beans as well.

Injecting Value Based Collections

Spring allows us to create beans that are wired with Collections and Arrays. In this post we shall create a simple class that has different collection based properties and then wire them with simple string values.

Injecting Properties Of Beans

Simply creating beans is not the only work of the container. We also need it to able to configure the newly instantiated beans. We need to 'inject dependencies' into these beans. There are two ways to inject the bean properties. One is using

The p namespace

<bean id ="band" class ="com.performer.Band">
    <property name="musician" ref="musician"></property>
    <property name="singer" ref="singer"></property>
</bean>

The above XML fragment