this is a "feature" but badly breaks RollingPurgeServlet in 2.4.3 in the case where the server is backed with a MemoryContext.

the failure mode is a null pointer exception; an OperatorException should be thrown that indicates that the context needs to be opened.

in a larger sense the Context lifecycle needs to be refactored by moving open/close semantics into sessions, and a workaround needs to be put in place for 2.4.x.