Why cann`t use GwtUserService or UserService in SsoCallbackServlet in the console?

[StevenWash]

Hi,
I have a problem in how to create a new user in the servlet named SsoCallbackServlet in the console.I want to use the accessToken in the method named doGet in the SsoCallbackServlet to create a new user ,and then use the UserService to store the new user into the user table.But ,it occurred errors like that:

And then ,I tried to use GwtUserService to do the same things above, and ,it occurred errors llike above.So,I want to ask how to create a new user using the infomations from the accessToken after the SsoCallbackServlet was called.
Thank you very mush!

[ctron]

Please have a look at the modules kapua-security-registration. They do exactly that.