title: Required @QueryParam in JAX-RS (and what to do in their absence)
body: <p>I deploy a web-services component to <strong>JBoss Application Server 7</strong> using the <strong>RESTEasy JAX-RS</strong> implementation.</p>
  
  <p>Is there an annotation available to declare required, mandatory <strong>@QueryParam</strong> parameters in <strong>JAX-RS</strong> ? And, if not, what is the 'standard' way to deal with situations where such parameters are missing?</p>
  
  <p>My web service (resource) methods return JSON-stringified results when properly invoked with all the mandatory arguments, but I'm not sure what is the best way to indicate to the caller that a required parameter was missing.</p>