Yes, its true, some environments disable annotation scanning for all projects, like jetty can

However, if this assumption of scanning or not is based on features in the servlet spec, such as metadata-complete, then you should know that with JEE7 / servlet 3.1 that configuration essentially has no impact on if annotation scanning should be done or not.

Example: if you are using javax.websocket on the server side, and have metadata-complete="true", then no endpoints could be deployed. Unfortunately, with a jsr-356 enabled container, you have to ignore the metadata-complete values and do annotation scanning anyway, albeit with a configuration that doesn't actually do anything with the servlet specific annotations it finds.