Oracle GlassFish Server 3.0.1 Application Development Guide

Header Management

In all Editions of the GlassFish Server, the Enumeration from request.getHeaders() contains multiple elements (one element per request header) instead of a single, aggregated value.

The header names used in HttpServletResponse.addXXXHeader() and HttpServletResponse.setXXXHeader() are returned as they were created.