Part I: Java[tm] Authentication and Authorization Service (JAAS) Class Libraries and Methods

//Java 2 interface to represent a Principal
import java.security.Principal;

//JAAS Authentication packages
import javax.security.auth.*;
import javax.security.auth.callback.*;
import javax.security.auth.login.*;
import javax.security.auth.spi.*;

public class Authenticate {

    public static void main(String[] args) {

        // Instantiate a LoginContext which will consult the configuration for the system and load all of the LoginModules
           configured. The LoginContext takes in the argument for the CallbackHandler that this application implements.

        // Invoke the login method on the LoginContext instance. Using a try-catch block, catch the LoginException
           exception if authentication fails, printing out the stack trace data and exits the application

        // If the login is successful, retrieve the authenticated Subject from the LoginContext

        // Use the doAs method on the Subject to invoke the intended application with the Subject

        // Exit the Authenticate application

    }

    class ThisAppCallbackHandler implements CallbackHandler {

        //Actual implementation of the CallbackHandler for this application.

  }

//Java 2 interface to represent a Principal
import java.security.Principal;

//JAAS Authentication packages
import javax.security.auth.*;
import javax.security.auth.callback.*;
import javax.security.auth.login.*;
import javax.security.auth.spi.*;

public class Authenticate {

    public static void main(String[] args) {

        //Instantiates a LoginContext. It consults the configurations to load all of the
        //LoginModules that is configured for this application. The assumption here is
        //that a CallBackhandler is required to obtain user input for the LoginModule to
        //authenticate.

        LoginContext logincontext = null;

        logincontext = new LoginContext("Aunthenticate", new ThisAppCallbackHandler());

        try {

            //Using the login() method to begin the authentication process
            logincontext.login();

        } catch (LoginException error) {

            System.out.println("The authentication was not successful due to " + error + " exception");
            error.printStackTrace();
                    System.exit(-1);
        }

        //Get the authenticated Subject if the login is successful
        Subject subject = logincontext.getSubject();

        //Executing the application ExecuteAuthApplication() as the authenticated Subject
        Subject.doAs(subject, new ExecuteAuthApplication());

        //Exiting this authentication application after the ExecuteAuthAppilcation application has started
        System.exit(0);

    }

    class ThisAppCallbackHandler implements CallbackHandler {

        // The actual implementation of the CallbackHandler is not described as this not the focus of
        // this code sample article. A CallbackHandler is implemented if the LoginModule must communicate
        // the user for input as part of the authentication process. For example, if the LoginModule
        // requires a password or smartcard pin number from the user of this application.

    }