/2007/10/19/tomcat-weak-etags-and-javascript-css-caching?format=rss en-us 40 Thoughts around my marriage to technology Interesting post! Which version of Tomcat are you running on? - I tried the code myself but there is no method called getAttributes() . At least none that doesn't take any arguments. Wed, 11 Jun 2008 08:36:53 -0700 urn:uuid:1d4a9ab7-804b-44c7-97f9-8a683ca1421b http://blog.bcarlso.net/2007/10/19/tomcat-weak-etags-and-javascript-css-caching#comment-12 Patrik, We were running TC 5.x. Sun, 15 Jun 2008 08:49:26 -0700 urn:uuid:1586436d-0dec-40d0-bcd9-013a125ae3ce http://blog.bcarlso.net/2007/10/19/tomcat-weak-etags-and-javascript-css-caching#comment-13 ...A "strong entity tag" MAY be shared by two entities of a resource only if they are equivalent by octet equality.... The way the etag is calculated in your example represents a weak etag, and what tomcat does by default. It's very likely for two entirely different files to be of same size and modified time. You need to use some digest algorithm to claim a strong etag. Mon, 05 Jan 2009 14:24:19 -0700 urn:uuid:9750c9b6-6685-42d3-8d96-dabf7b6244fa http://blog.bcarlso.net/2007/10/19/tomcat-weak-etags-and-javascript-css-caching#comment-19 @ptys Good point. From the same spec: "Entity tags are used for comparing two or more entities from the same requested resource". <blockquote> It's very likely for two entirely different files to be of same size and modified time. </blockquote> True. But two entirely different files to be of the same size and modified time for a given resource? I think that's a bit less likely. I chose to usurp TC's ETag implementation as I deemed it "Good Enough". <br /> Thanks for the clarification. Mon, 05 Jan 2009 16:46:14 -0700 urn:uuid:c9333b89-ba3b-45c2-9a90-f0ccdba7f7e9 http://blog.bcarlso.net/2007/10/19/tomcat-weak-etags-and-javascript-css-caching#comment-20