There are three different JAVA packages in the JAXB binding framework, which include the following :
xml.bind : It helps in defining the abstract classes and interfaces which are directly connected with the content classes.
xml.bind.util : It consists of utility classes that can be availed by client applications with the purpose to manage marshaling, validation, and unmarshalling events.
xml.bind.helper : It gives partial implementation for javax.xml.bind interfaces.
These API cannot be directly used by the applications which are already executing JAXB architecture.