About Beans (original) (raw)

CDI redefines the concept of a bean beyond its use in other Java technologies, such as the JavaBeans and Enterprise JavaBeans (EJB) technologies. In CDI, a bean is a source of contextual objects that define application state or logic. A Java EE component is a bean if the lifecycle of its instances may be managed by the container according to the lifecycle context model defined in the CDI specification.

More specifically, a bean has the following attributes:

• A (nonempty) set of bean types
• A (nonempty) set of qualifiers (see Using Qualifiers)
• A scope (see Using Scopes)
• Optionally, a bean EL name (see Giving Beans EL Names)
• A set of interceptor bindings
• A bean implementation

A bean type defines a client-visible type of the bean. Almost any Java type may be a bean type of a bean.

• A bean type may be an interface, a concrete class, or an abstract class and may be declared final or have final methods.
• A bean type may be a parameterized type with type parameters and type variables.
• A bean type may be an array type. Two array types are considered identical only if the element type is identical.
• A bean type may be a primitive type. Primitive types are considered to be identical to their corresponding wrapper types in java.lang.
• A bean type may be a raw type.