How to ask for Prototype bean in Spring service class without applicationContext

Ritam Das :

I have a component defined with prototype scope. I want to use that component in my service class. I want spring to provide me a new instance of that Bean everytime I call for it.

Component Class:

@Getter
@Setter
@Component
@Scope("prototype")
public class ProtoTypeBean {
  //.. Field variables
}

Service Class:

@AllArgsConstructor
@Service
public class ServiceClass {
    ProtoTypeBean prototypeBean;
    ArrayList<ProtoTypeBean> prototypeBeans;
    public void demoMethod(ArrayList<String> someArrayList) {

        for(var singleString: someArrayList) {
            prototypeBean.setFieldValue(singleString);

            prototypeBeans.add(prototypeBean);              
        }
        System.out.println(prototypeBeans.toString());
    }
}

By using this configuration, I am getting the same instance of ProtoTypeBean in my prototypeBeans ArrayList. The question is, how would I make Spring understand to give me a new instance of prototypeBean every time I am calling it into the foreach loop? I found I can use ApplicationContext.getBean() to get a new instance of the Bean in foreach loop but I also heard that it's a bad practice. So kindly help me with the best practice.

M. Deinum :

Use an ObjectProvider to lazily get the result you want. However the first prototype scoped bean will not be represented in the list of beans as, well they are prototype scoped.

@AllArgsConstructor
@Service
public class ServiceClass {

    private final ObjectProvider<ProtoTypeBean> provider;

    public void demoMethod(ArrayList<String> someArrayList) {
        PrototypeBean pb = provider.getIfUnique();
        for(var singleString: someArrayList) {
            pb.setFieldValue(singleString);
            pb.add(prototypeBean);              
        }
        System.out.println(prototypeBean.toString());
    }
}

Also if you don't need all the dependency injection, proxy creation etc. for your object then why bother. There is nothing wrong with just the new keyword in a Spring application. Not everything has to be managed by Spring.