code: private RestException buildKnown(Constructor<RestException> constructor, RestFailure failure)
  	{
  		try
  		{
  			return constructor.newInstance(failure.exception.detail, null);
  		}
  		catch (Exception e)
  		{
  			return buildUnknown(failure);
  		}
  	}
docs: Build an exception for a known exception type
  
  @param constructor
  @param failure
  
  @return