JBoss Weld CDI for Java Platform

Definition of a bean

A bean is simply a Plain Old Java Object (POJO) that is managed by a container instead of an application. With this simple definition of a bean, most of your existing Java classes can be utilized as beans with minimal to no changes, such as adding annotations.

public class MyFirstBean {
}

It may not look like much, but the preceding Java class is all that is required for the most basic of CDI beans, which use the @Dependent scope (see Chapter 4, Scopes and Contexts).

To specify a CDI scope other than @Dependent, the bean will need a means for Weld to generate a Proxy (see Chapter 2, Dependency Injection and Lookup) of the bean for injection. For a bean to be able to be proxied by the container, it needs a non-private constructor ...