String tenantId = "************";
    String username = "***************";
    String password = "*************";
    String clientId = "**********";
    String resource = "***********";
    String userEmail = "**********";


    AuthenticationContext authContext = null;
    AuthenticationResult authResult = null;
    ExecutorService service = null;

    try
    {
        service = Executors.newFixedThreadPool( 1 );
        String url = "https://login.microsoftonline.com/" + tenantId + "/oauth2/authorize";
        authContext = new AuthenticationContext( url, false, service );
        Future<AuthenticationResult> future = authContext.acquireToken(
                resource,
                clientId,
                userEmail,
                password,
                null );

        authResult = future.get();

    }
    catch( Exception ex )
    {
        ex.printStackTrace();
    }

public AuthenticationResult AcquireTokenByRefreshToken(
string refreshToken,
string clientId,
string resource
)