The JavaBeans Activation Framework (JAF) is a standard extension to the Java platform that lets you take advantage of standard services to: determine the type of an arbitrary piece of data; encapsulate access to it; discover the operations available on it; and instantiate the appropriate bean to perform the operation(s).
JAF is used by JavaMail and JAX-WS for data content handling.
JAF is included in Java SE 6 and later.