Using web.xml, select a communication path encryption level. Definitions in DD files are as follows.

• The security-constraint-user-data-constraint tag
  Use this tag to select an encryption level for encrypting authentication information and data by using SSL.
  

You can use web.xml to configure the settings for a Web application before deploying the application on the J2EE server. You can use an attributes file to configure the same settings for a Web application already deployed on the J2EE server. For details about the settings in attributes files, see 7.2.7(2) Configuring the J2EE application.