Oltu Authorization Server

protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

    try {
         //dynamically recognize an OAuth profile based on request characteristic (params,
         // method, content type etc.), perform validation
         OAuthAuthzRequest oauthRequest = new OAuthAuthzRequest(request);

         validateRedirectionURI(oauthRequest)

         //build OAuth response
         OAuthResponse resp = OAuthASResponse
             .authorizationResponse(HttpServletResponse.SC_FOUND)
             .setCode(oauthIssuerImpl.authorizationCode())
             .location(ex.getRedirectUri())
             .buildQueryMessage();

         response.sendRedirect(resp.getLocationUri());

         //if something goes wrong
    } catch(OAuthProblemException ex) {
         final OAuthResponse resp = OAuthASResponse
             .errorResponse(HttpServletResponse.SC_FOUND)
             .error(ex)
             .location(redirectUri)
             .buildQueryMessage();

         response.sendRedirect(resp.getLocationUri());
    }

}

Response.status(resp.getResponseStatus()).location(resp.getLocationUri()).build();

protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

OAuthTokenRequest oauthRequest = null;

OAuthIssuer oauthIssuerImpl = new OAuthIssuerImpl(new MD5Generator());

    try {
           oauthRequest = new OAuthTokenRequest(request);
	   
           validateClient(oauthRequest);

           String authzCode = oauthRequest.getCode();

           // some code
           String accessToken = oauthIssuerImpl.accessToken();
           String refreshToken = oauthIssuerImpl.refreshToken();

           // some code
            OAuthResponse r = OAuthASResponse
                .tokenResponse(HttpServletResponse.SC_OK)
                .setAccessToken(accessToken)
                .setExpiresIn("3600")
                .setRefreshToken(refreshToken)
                .buildJSONMessage();

        response.setStatus(r.getResponseStatus());
        PrintWriter pw = response.getWriter();
        pw.print(r.getBody());
        pw.flush();
        pw.close();
         //if something goes wrong
    } catch(OAuthProblemException ex) {

        OAuthResponse r = OAuthResponse
            .errorResponse(401)
            .error(ex)
            .buildJSONMessage();

        response.setStatus(r.getResponseStatus());

        PrintWriter pw = response.getWriter();
        pw.print(r.getBody());
        pw.flush();
        pw.close();

        response.sendError(401);
    }

}