Again, something to weigh. If I do this: private static final String getLocalName(HttpServletRequest request) { | String localAddr = request.getLocalAddr(); | String localName = localAddr_to_localName.get(localAddr); | if (localName == null) { | localName = request.getLocalName(); | localAddr_to_localName.put(localAddr, localName); | } | return localName; | } | private static final Map<String,String> localAddr_to_localName = Collections.synchronizedMap(new HashMap<String,String>()); The it is thread safe, but opens the door for multiple calls to request.getLocalName(). But if I do this: private static final String getLocalName(HttpServletRequest request) { | String localAddr = request.getLocalAddr(); | synchronized (localAddr_to_localName) { | String localName = localAddr_to_localName.get(localAddr); | if (localName == null) { | localName = request.getLocalName(); | localAddr_to_localName.put(localAddr, localName); | } | return localName; | } | } | private static final Map<String,String> localAddr_to_localName = new HashMap<String,String>(); Then request.getLocalName() will only ever get called once, since both the get and put calls to the map are in the same atomic block. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4269383#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...