Integrate openid4java to GWT Project

Answer 1

You are using Google App Engine. GAE restricts the libraries that can be used in an application. In particular, creating threads or accessing the network are prohibited.

The stack trace you pasted shows openid creating a java, and GAE blocking it.

If you don't care about GAE, just disable it in eclipse settings. Once you do that, you should be able to use the library.

If you also want to use GAE, then you will have to find an alternative to OpenId4Java. Somebody else may have an alternative to that.

Answer 2

I think you're missing the servlet entry in web.xml

<servlet>
  <servlet-name>OpenIdServlet</servlet-name>
  <servlet-class>path.to.your.servlet</servlet-class>
</servlet>

<servlet-mapping>
  <servlet-name>OpenIdServlet</servlet-name>
  <url-pattern>/openid/openid</url-pattern>
</servlet-mapping>

Answer 3

Due to the restrictions of GAE you can't use openid4java directly. You can try this modified version: http://github.com/WdWeaver/openid4java-gae-hacks