The Callback interface is defined in the javax.auth.security. callback package, which is provided with the SDK in jaas.jar. A current version of jaas. jar can be obtained from http://java.sun.com. The javadoc documentation for the interface provides the following description of javax.auth.security.callback.CallbackHandler.
An application implements a CallbackHandler and passes it to underlying security services so that they may interact with the application to retrieve specific authentication data, such as user names and passwords, or to display certain information, such as error and warning messages.
|"javax.security.sasl.encryption.minimum"||Minimum key length; ...|