Wt

In JWt, WebSession::appendSessionQuery() will manually construct and encoded URL if the response is null.
Some servlet containers invalidate Request and Response objects to be reused later, but do not discard them, for efficiency. Tomcat 9.0.35, for example, will throw a NullPointerException when calling most of the methods on the object, while Tomcat 9.0.105 will catch this case specifically and throw an IllegalStateException when trying to use any of the methods.

We can catch these cases and handle them just as where the Response would be null.