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If you do not require a full stack of interceptors for an Action, then try using a different one (basicStack), or remove interceptors you do not need. Remove the I18nInterceptor interceptor if you don't need it, as it can cause a session to be created.

Use the correct HTTP headers (Cache-Control & Expires).

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Struts 2 does not create sessions unless asked to (for example, by having the createSession interceptor in your interceptor stack). Note that when you use SiteMesh however, a session will always be created (See http://forums.opensymphony.com/thread.jspa?messageID=5688 for details). The I18nInterceptor interceptor can create sessions, so make sure you remove it, if you don't need it.

When using Freemarker, try to use the Freemarker equivalent rather than using the JSP tags.

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