This is similar to the other extension HttpSessionScope. Traditionally JAX-WS has never taken advantage of object state, just like servlet. That is, the container creates only one instance of your service class, and then have it serve all the requests concurrently. This makes it impossible to set values to instance fields, as you'll experience concurrency problem as soon as multiple threads hit...
Few months back, Kohsuke
mentioned about Tubes
in his blog JAX-WS
RI goes truly asynchronous!
That time, it was working only in prototypes. Now JAX-WS 2.1 runtimes
completely works on Tubes. The javadoc for Tube says, "Tube is a basic
processing unit that represents SOAP-level protocol handling code.
Multiple tubes are often put together in a line, and act on Packets...