Constructor Injection with Non-String Collection (having Dependent Object) Example

If we have dependent object in the collection, we can inject these information by using the ref element inside the list, set or map.

In this example, we are taking the example of Forum where One question can have multiple answers. But Answer has its own information such as answerId, answer and postedBy. There are four pages used in this example:

1. Question.java
2. Answer.java
3. applicationContext.xml
4. Test.java

In this example, we are using list that can have duplicate elements, you may use set that have only unique elements. But, you need to change list to set in the applicationContext.xml file and List to Set in the Question.java file.

This class contains three properties, two constructors and displayInfo() method that prints the information. Here, we are using List to contain the multiple answers.

This class has three properties id, name and by with constructor and toString() method.

The ref element is used to define the reference of another bean. Here, we are using bean attribute of ref element to specify the reference of another bean.

This class gets the bean from the applicationContext.xml file and calls the displayInfo method.