Question

I am using a @ManagedBean(request scoped) as a @ManagedProperty inside another @ManagedBean. However the bean(one used as a @ManagedProperty) at the time of usage is un-instantiated and therefore leads to NullPointerException.

How can I resolve this issue ?

Answer 1

You’re apparently trying to access it in the constructor of the parent bean. This is indeed not possible. The managed properties are injected after construction.

ParentBean parentBean = new ParentBean(); // Constructor invoked.
parentBean.setChildBean(new ChildBean()); // Managed property set.

The earliest access point is a @PostConstruct method. It’s invoked after construction and managed property (and all other dependency like @EJB) injection.

@ManagedProperty("#{childBean}")
private ChildBean childBean;

@PostConstruct
public void init() {
    System.out.println(childBean); // Not null.
}